When Knowledge and Ethics Collide

Scientists can change an organism’s genes. Should they?

Our ability to change living things grows as we learn more about life. But sometimes biotechnology makes us question whether we should change organisms just because we can. Maybe the technology is dangerous or maybe it challenges our values. Consider the greenish pig in the photo. A gene from a fluorescent jellyfish was added to its genome by genetic engineering. No harm done, in this case. But how and when should we alter an organism’s genes?

Bioethics

Bioethics is the study of moral questions that are raised as a result of biology research and its applications. But what do questions of ethics have to do with biology? It might seem better to leave questions about values in a philosophy or social studies class. But keep your mind open as you learn more about the power of biological research to alter living things and to reveal new types of information. You might find that your biology class is the perfect place to consider any number of ethical questions.

Ethical questions require all of us to make decisions about “the right thing to do.” Often, the right thing to do is very clear. Do we cheat on a test, or do we study and learn the material for ourselves? A good decision can benefit ourselves, our families, and even our society—and it often follows the accepted values of society. However, many times the “right” and “wrong” about an ethical issue are not so obvious. Strong feelings on both sides of an ethical question can produce conflicts—in ourselves, and for everyone involved. Can we rely upon biology, or any other scientific field, for our decisions?

Potential Benefits

There are some obvious benefits to having biological information more easily accessible. The Innocence Project, for example, as of 2010 has freed more than 260 prisoners who were wrongfully convicted—some of them on death row—based on incorrect or incomplete evidence. In this case, DNA technology can add new facts to an old story and actually save a person’s life.

In less dramatic ways, biological information can help people live longer and healthier lives. Tests can reveal whether someone is prone to gum disease, heart attacks, Alzheimer’s, or certain kinds of cancer. With this information—now available through at–home saliva tests—people can tailor their exercise, diet, and other lifestyle choices to guard against actually contracting these diseases. Access to biological information in this case can be empowering, and can help people live healthier lives.

Controversial Issues

With genetic information much more easily accessible, new questions arise. Can a DNA–testing facility, for example, be trusted to keep your results private? This issue of right to information has taken many turns during the past decade. In 2008, the United States passed a law called the Genetic Information Nondiscrimination Act (GINA). This law protects all citizens from potential discrimination by employers and insurers: Even if genetic testing does reveal an individual’s likelihood for developing certain health problems, an insurer cannot deny this person coverage based on this information. Do you think this law is necessary? Would you be more likely to get DNA testing knowing that this law is in place?

Aside from issues of privacy, what do your lifestyle and health decisions look like if you do test positive for a fatal disease? Although DNA testing is more accurate than many other tests, there is still a possibility of incorrect results. Even if they are correct, there is the possibility that a cure will come for any given disease within your lifetime. Families with the gene for a neurological disorder called Huntington’s disease, for example, often do not elect to be tested. Some individuals do not want this information—bad or good—to affect their lives. How does having this information improve or limit your choices?

Science can only provide information and possibilities. We can add new genes to an organism’s DNA. We can clone animals and may someday clone humans. We can extend human life expectancies. We can test people’s risk for diseases. But should we do all these things? Should government continue to make laws regarding bioethical issues? Should people be able to make their own decisions about personal health and privacy? As biotechnology continues to advance, you will face new bioethics questions throughout your lifetime. Will you be ready?

Questions to Consider

  • Should scientists do all of the things that technology has made it possible for them to do?
  • Should individuals or the government decide how biotechnology is used?
  • Should scientific knowledge or personal beliefs be more important in decisions about biotechnology?

Updates: Straight from the Headlines

Genetic Testing

Genetic testing is used in many ways. We can identify disease–causing genes, determine the guilt or innocence of crime suspects, and reunite families that have been separated. But should genetic testing be used by employers to make decisions about employees?

Suppose that a company secretly obtained and tested DNA samples from some of its employees. Because of rising medical insurance claims, the company wanted to know if the employees had a gene that increased their risk for developing a certain medical condition. Does this seem like a plot for a television show? It isn’t. In 2002, a company had to pay more than $2 million in damages for testing the DNA of employees without their knowledge.

Consider another case. In 2005, a basketball player named Eddy Curry missed the end of the season due to a potential heart problem. His team wanted to use a genetic test to find out if he had a life–threatening condition. Curry refused because the test results could have ended his career. The team refused to let him play. Both the team and Curry made choices. Who do you think was right?

Geneticist in Action

Dr. Charmaine Royal
Title: Professor, Pediatrics, Howard University
Education: Ph.D., Human Genetics, Howard University

Many bioethicists focus on the ethical implications of technology. Dr. Charmaine Royal, however, is concerned with the ethics of experimental design and the applications and implications of biological research. Dr. Royal, who is a geneticist at the Human Genome Center of Howard University, points out that some scientists in the past tried to use genetic research to justify treating non–Caucasians as inferior. She also notes that although there is no biological basis for any meaningful differences among races, many African Americans are still suspicious of genetic research. Many, for example, have been discriminated against when an insurance company or a prospective employer finds out they have sickle cell anemia, which is a relatively common genetic disorder in African Americans. Dr. Royal, who is Jamaican, wants to ensure that African Americans are included and treated fairly in research studies, and that they receive the benefits of genetic screening and genetic counseling. In 1998 Dr. Royal helped start the African American Hereditary Prostate Cancer Study, the first large–scale genetic study of African Americans to be designed and carried out by an almost entirely African American research team.

Stem Cell Research—Potential Solutions, Practical Challenges

A group of embryonic stem cells. (colored SEM magnification 1000x)

A news program asks viewers to vote online: “Should stem cell research be banned? Yes or no?” Some people claim that stem cell therapy will revolutionize medicine. Others believe that some types of stem cell research violate ethical standards and are not justified by the potential benefits. Between these two positions exists a wide range of ideas about what is or is not acceptable. Would you know how to vote?

Using Stem Cells

Stem cells are undifferentiated cells that can regenerate themselves and develop into specialized types of cells. Stem cell research offers the hope of understanding basic cell processes and treating or even curing many diseases. However, many technical challenges must be overcome before stem cell therapy is a realistic option, and ethical issues continue to surround stem cell research.

Potential Benefits

Stem cell research offers many potential benefits.

  • Studying adult stem cells may help scientists better understand how tissues develop and what goes
    wrong when those tissues become diseased.
  • A better understanding of the properties of stem cells may give scientists more information about
    how cancer cells replace themselves and thus help scientists develop more-targeted cancer therapies.
  • Stem cells could be used to grow human tissues to test the effects of drugs and chemicals.
  • Stem cells may be used to replace healthy cells that are killed by radiation treatment for cancer.
  • Stem cells may be used to regenerate tissues. For example, chemotherapy kills blood– producing cells in bone marrow. To replace these cells, stem cells could be used instead of the patient’s own marrow, which may contain cancer cells.
  • Stem cells may be used to treat spinal cord injuries and neurodegenerative diseases, such as
    Parkinson’s.

Technical Challenges

Adult stem cells have been used therapeutically for years in the form of bone marrow transplants. Nevertheless, many technical challenges must still be overcome before stem cells can be used to treat a wide range of disorders. Examples are highlighted below.

Supply Stem cells can be taken from a variety of sources, including an embryo, a patient in need of treatment, a patient’ relative, or an established embryonic stem cell line. Embryonic stem cells are taken from embryos fertilized in an in vitro fertilization clinic, whereas established stem cell lines are cultures of embryonic stem cells used to grow additional stem cells that match the ones that came from the original embryo. Each source presents its own special set of ethical considerations.

Transplantation into the target area The delivery of stem cells to targeted tissues can be complex, especially if the tissues are deep inside the body. And once delivered, stem cells must “learn” to work with other cells. For instance, inserted cardiac cells must contract in unison with a patient’s heart cells.

Prevention of rejection Stem cells may be rejected if a patient’s body sees them as foreign. This problem can remain even when certain identifying proteins are removed from the cells’ membranes. The development of SCNT technology in humans could help solve this problem so that patients would not have to take drugs to suppress their immune system.

Suppression of tumor formation By their very nature, stem cells remain undifferentiated and continue to divide for long periods of time. When transplanted into an organism, many embryonic stem cells tend to form tumors. This risk must be removed before the cells can be used therapeutically.

Unanswered Questions

Stem cell research and therapy do not only involve questions of what we can do. They also involve
questions about what we should do, who should benefit, and who should pay.

  • Should human embryos be a source of stem cells?
  • How should stem cell research be funded?
  • How can the benefits of stem cell research best be shared by all people, regardless of income?
  • Should insurance cover costly stem cell procedures?

UPDATES: Straight from the Headlines

Somatic Cell Nuclear Transfer

Somatic cell nuclear transfer (SCNT), also called therapeutic cloning, is a method for obtaining stem cells that has been used to clone animals. The process is still under development, however, and it has not yet been used to produce stem cells for humans. SCNT offers the hope of using a patient’s own DNA to produce stem cells that can form many types of specialized cells. Many SCNT studies have been done in mice and pigs; the diagram to the right shows how the SCNT process might be applied in human
cells.

  1. An unfertilized egg is taken from a female’s body, and the nucleus—containing the DNA—is removed. A cell is then taken from a patient’s body. The nucleus is removed and inserted into the egg.
  2. The egg is given a mild electrical stimulation, which makes it divide. The DNA comes from the patient’s nucleus, and the materials needed for division come from the egg.
  3. The stem cells could then be cultured and caused to differentiate into any tissue or organ needed by the patient.

Once a stem cell line is established, in theory it can continue to grow indefinitely. Researchers could use these cell lines without having to harvest more stem cells. The cell lines also could be frozen and shipped to other researchers around the world.

Cell Biologist in Action

 

Dr. Gail Martin

Title: Professor, Anatomy, University of California, San Francisco
Education: Ph. D., Molecular Biology, University of California, Berkeley

In 1974 Dr. Gail Martin was working at the University College in London when she made a huge advance. She developed a way to grow stem cells in a petri dish. These fragile cells were hard to work with, so Dr. Martin’s breakthrough removed a big obstacle to stem cell research. Seven years later, she made another key discovery while working in her own laboratory at the University of California, San
Francisco, in her native United States—how to harvest stem cells from mouse embryos. Her work has helped other scientists develop ways to harvest stem cells from human embryos and explore their
use in treating disorders.

Dr. Martin likes to point out that her work shows how small advances in basic biology can pay off years later in unexpected ways. She states that many people focus on cures for specific diseases, not realizing that these cures “may come from basic research in seemingly unrelated areas. What is really going to be important 20 years from now isn’t clear.”

Medical Technology—The Genetic Forefront

surgery

A patient receives an operation following an adverse drug reaction.

A college student comes down with the flu. Worried about missing class, he goes to an emergency clinic and is given a prescription for an antiviral flu drug. Thirty minutes after taking the first pill, he is gasping for breath and his heart is racing. He is rushed to the hospital, where doctors tell him he has had an adverse reaction to his antiviral medication.

A Cure Worse than the Disease

Usually, medications cause only mild side effects, such as drowsiness, headaches, or nausea. Occasionally, patients are allergic to medicines and break out in hives or go into shock. But sometimes reactions to drugs are more serious. In the United States, about 2.2 million patients per year are hospitalized because of adverse drug reactions, and more than 100,000 die. No doctor intends for a drug’s side effects to be worse than the disease it is meant to cure. Nonetheless, the current process of prescribing drugs based on medical and family history is one of trial and error.

Customized Drugs

An emerging field called pharmacogenomics is revolutionizing the prescription process. Pharmacogenomics is the study of how genetic variations can cause different people to react in different ways to the same drugs. In most cases, for example, genetics determines the way in which—and the speed at which—a person’s body breaks down a medication. If a person’s body metabolizes a drug too quickly, the drug may not be effective. If the drug is metabolized too slowly, a standard dose may be too much.

In the future, a patient in need of a prescription could have a blood test, and health care workers could run the blood test results through a computer using biochip, or microarray, technology. In hours, a doctor could have enough information about a patient’s genetic background to predict how the person would respond to a certain drug and decide whether to adjust the dose. Individuals may even be able to have their genomes mapped and put onto cards to take to doctor visits. Biochip technology is not yet available in most doctors’ offices, but many drugs are already being labeled with pharmacogenomic information advising doctors that patients with certain genetic variations may need a lower or higher dose of the medication.

Gene Therapy

While pharmacogenomics can provide doctors with more information about their patients, gene therapy may someday provide them with another tool. Some diseases, such as Alzheimer’s or hemophilia, have a strong genetic basis. Doctors are beginning clinical trials in which they treat Alzheimer’s by injecting genes, during surgery, into the area of the brain that has the most affected brain cells. The new genes will instruct brain cells to make more of a protein that keeps nerve cells alive longer.

Doctors are also beginning to treat hemophilia using gene therapy. One method is to inject genes into the liver. In other clinical trials, new DNA is inserted into a virus that can then be used to “infect” a patient’s diseased cells. The field of gene therapy is developing slowly because it requires researchers to accomplish several feats. First, they must engineer, and test, a gene that is safe to insert into humans. Then they must find a way to get the gene to the part of the body that needs it—often using nanotechnology. Much of this research is still being done in animals, but there have been a few successful gene therapy trials in humans.

Other Uses

A scientist examines different types of genetically modified rice plants.

New uses for DNA technology offer both solutions and hard choices. Some of the more difficult questions involve the following kinds of projects:

  • Researchers can alter the DNA of viruses to make them harmless and usable as vaccines.
  • Scientists are developing transgenic animals that can make organs for human transplants.
  • Researchers are engineering crops that contain vaccines that could be administered orally. These
    vaccines would be easier to grow and distribute in developing countries than are current vaccines.

Unanswered Questions

Some exciting new pharmacogenomic research is being done by the Human Genome Project. However, many challenges must be addressed before pharmacogenomics can have widespread clinical application.

  • Many current studies of patients’ drug responses have conflicting results, likely due to small sample
    sizes, different criteria for measuring a good response, and different population groups.
  • Patients’ responses to a drug may be caused by many genes. Scientists will need to study the effect
    of multiple genes to determine response.
  • Genotype testing may increase short-term healthcare costs, raising questions about who will pay and who will have access to the technology.

UPDATES: Straight from the Headlines

Biochips

Doctors can now analyze a patient’s DNA by using biochip technology. A biochip is a solid surface to which tiny strands of DNA are attached. When this type of screening becomes clinically feasible, it will take several steps.

  1. DNA will be extracted from the patient’s blood.
  2. A biochip will be used to map the patient’s genome. Computer software could scan the genome looking for single nucleotide polymorphisms (called SNPs, or “snips”), places where human DNA is more variable.
  3. A doctor will then compare the patient’s genomic results with the latest available medical research.

Ideally, the resulting prescription should be customized to the patient. If a patient has a variation that is found in a small percentage of the population, however, the doctor is unlikely to have enough data about possible reactions.

Cancer Geneticist in Action

Dr. Olufunmilayo Olopade
Title: Director, Center for Clinical Cancer Genetics, University of Chicago
Education: M.D., University of Ibadan, Nigeria

Breast cancer occurs in many different forms. It has been most widely studied in Caucasian women but takes a very different form in women of African ancestry. Breast cancer hits women of African ancestry earlier and more aggressively than it does Caucasian women. Dr. Olufunmilayo Olopade wants to learn why. Working with scientists in her native Nigeria, Dr. Olopade compared gene expression in samples of cancer tissue from African women with samples of cancer tissue from Canadian women. She found that cancer cells from the African women often lacked estrogen receptors. This finding means that many of the standard treatments are not effective for this group of women.

Dr. Olopade’s work will have a huge impact on breast cancer screening and treatment in women of
African ancestry. “Cancer doesn’t start overnight,” she says. “We can develop strategies for preventing it.”

Drug-Resistant Bacteria—A Global Health Issue

Could a scraped knee land you in the hospital?

A bicyclist falls, scrapes his knees, and within a few days is unable to walk. Soccer players with turf burns suddenly find themselves in the hospital with skin infections that require
intravenous antibiotics. Why are these young, healthy athletes developing such serious infections?

Staph Infections

These athletes were infected by Staphylococcus aureus, or “staph.” Staph is a common bacteria that most people carry on the surface of their skin and in their nose. To cause an infection, staph bacteria must get inside your body. The scrapes athletes commonly get provide an ideal entrance.

Serious problems due to staph infections used to be rare. Doctors would prescribe antibiotics, such as penicillin, to kill the staph bacteria. Ordinary staph infections can still be treated this way. The athletes in our examples did not have ordinary infections. These athletes’ scrapes were infected by methicillin-resistant Staphylococcus aureus (MRSA). This bacteria strain is one of many that has evolved resistance to antibiotics.

Drug-Resistant Bacteria

Bacteria that can survive antibiotic treatment are called drug-resistant bacteria. Some bacteria have resistance for one particular antibiotic, some have resistance for several, and a few cannot be treated with any known antibiotic.

MRSA can resist an entire class of antibiotics. Patients with an MRSA infection must often be treated with what doctors call “the drug of last resort,” vancomycin. Vancomycin is a drug that must be given intravenously. Not surprisingly, doctors began to see cases of vancomycin-resistant Staphylococcus aureus (VRSA) in 1997. By 2010, vancomycin-resistant bacteria were being discovered in the droppings of one out of ten seagulls, leading scientists to postulate that migrating birds may play a role in spreading drug-resistant “superbugs.”

Staph isn’t the only type of bacteria that is making a comeback with drug-resistant strains. In the mid-twentieth century, antibiotics nearly wiped out tuberculosis (TB). But in the 1990s, TB began to approach epidemic numbers again, and now it kills more than 2 million people every year. Drug-resistant TB kills thousands. Drug-resistant strains of cholera and bubonic plague also have been reported.

How Does Drug Resistance Evolve?

The incidence of MRSA infections is on the rise.

When you take antibiotics for a bacterial infection, billions of bacteria may be killed right away. However, a few likely survive. Antibiotics leave behind the more resistant bacteria to survive and reproduce. When they reproduce, the genes that make them resistant are passed on to their offspring. Some bacteria reproduce rapidly—E. coli, for example, doubles its population every 20 minutes.

In addition to their ability to reproduce quickly, populations of bacteria evolve rapidly. Bacteria use plasmids—small loops of DNA—to transfer genetic material between individual cells. This process is called conjugation. Some plasmids pass on resistance for one particular antibiotic. Others can transfer resistance for several antibiotics at once.

What characteristics do resistant bacteria pass on to their offspring? Some have cell membranes through which antibiotics cannot easily pass. Others have pumps that remove antibiotics once they enter the cell. Some can even produce enzymes that attack the antibiotic drugs themselves.

Fighting Back

Some scientists are trying to develop ways to treat patients without killing the bacteria that are making them sick. Instead, they target the toxins produced by bacteria. If the bacteria are not harmed by the treatment, no selective pressure is produced. Scientists hope that by using this approach, bacteria will be slower to evolve defense mechanisms against the antibiotics. Other scientists hope to fight back by using bacteria’s ancient rival, bacteriophages, which are viruses that infect bacteria.

Unanswered Questions

Some important research questions involving drug-resistant bacteria include the following:

  • Can plasmids or bacteriophages be used in vaccines to fight bacteria?
  • Are bacteria being exposed to antibiotics in sewage systems and evolving resistant strains there?
  • How do antibacterial soaps and household cleaners contribute to the evolution of drug-resistant
    bacteria?
  • Can drug-resistant bacteria be transferred from domestic animals to humans through food?

UPDATES: Straight from the Headlines

New Drug Delivery System

Staph bacteria

Staph bacteria

Researchers at Yeshiva University decided to take on one of the most difficult bacterial infections of all, methicillin-resistant staph. They have developed a treatment using nanoparticles that can be delivered directly to a wound on the skin.

  • Tiny nanoparticles carry nitric oxide (NO), which helps the immune system respond to infection.
  • The nanoparticles are applied topically, to deep, infected skin abscesses.
  • The nanoparticles absorb water, swell, and release NO. NO kills bacteria and dilates blood vessels, to speed healing.

Because the bacteria are “eating” the nanoballs, cell wall adaptations that once kept antibiotics out are no longer an obstacle.

Evolutionary Biologist in Action

Dr. Richard Lenski
Title: Professor, Microbial Ecology, Michigan State University
Education: Ph. D., Zoology, University of North Carolina, Chapel Hill

If you want to observe evolution in action, you must find populations that reproduce quickly. Dr. Richard Lenski, a professor at Michigan State University, has done just that. Dr. Lenski studies populations of E. coli bacteria, which he grows in flasks filled with a sugary broth. These bacteria produce about seven generations each day. Dr. Lenski has now observed more than 30,000 generations of E. coli.

The rapid rate of E. coli reproduction allows Dr. Lenski to watch evolution take place. Dr. Lenski can subject each generation of bacteria to the same environmental stresses, such as food shortages or antibiotics. He then can compare individuals from more recent generations with their ancestors, which he keeps in his laboratory freezer. By comparing generations in this way, Dr. Lenski can study how the population has evolved.

When Dr. Lenski began his research in 1988, watching evolution in action was still new. Now, many
evolutionary biologists are following in his footsteps.

Climate Change—Changing the Planet

As global temperatures rise and arctic ice melts, polar bears are losing important hunting grounds.

Polar bears are on the move. The area of arctic sea ice on which these carnivores hunt seals has declined 34 percent as worldwide temperatures rise. As this ice is lost, polar bears must swim as far as 100 kilometers (about 60 mi) to find their prey. Some of these polar bears cannot make it, and they drown. Now polar bears must compete with grizzly bears. If climate change is changing the shape of one of Earth’s coldest regions, how will it affect the rest of our planet?

Ecosystems at Risk

In the 20th century, the average global temperature rose by 0.6ºC (1ºF). The difference may seem small, but it is an average for the entire globe. Near the poles, the effects of climate change are more dramatic. Since 1949, average annual temperatures in Alaska have risen 1.8ºC (3ºF)—enough to lengthen the summer melting season for sea ice and glaciers. From 1979 to 2007, Arctic sea ice retreated enough to expose an additional one million square miles of open water—the equivalent of six Californias.

Good and Bad News?

In the rest of the world, the impact of climate change on Earth’s species may be mixed. Many animal species, such as birds and butterflies, can move to cooler areas as the climate warms. But insects and microorganisms that cause infectious diseases, such as malaria and yellow fever, are also spreading toward the poles. Some plant species cannot move as quickly as the climate is expected to change, and may become extinct.

Computer modeling programs such as this one work to predict the effects of global warming by simulating different temperature increases.

Researchers are also finding that changing temperatures can affect animals in surprising ways. The sex of some reptiles, for example, is partially determined by the temperature of the developing egg. A consistent warming trend could cause some reptiles to become extinct by creating entire generations that are all the same sex. Migratory birds and marine mammals also face challenges. For example, birds that wait until their normal migration time to fly north in the spring may arrive too late, missing the best weeks for laying eggs and catching the insects they need to raise their young. In addition, some researchers have predicted that the productivity of phytoplankton, the algae on which ocean food webs are based, may decline in some areas. A change of this sort could cause a domino effect in marine food webs. If phytoplankton levels decline, fish will have less food and will be less numerous. If fish are less numerous, marine mammals and birds will have less to eat too. In addition, studies show that this increase in global temperatures is linked to a four percent increase in ocean humidity and a six to eight percent increase in rainfall, leading to stronger hurricanes.

But the news may not be all bad. Some of the same research shows that the same factors that increase the strength of a hurricane also make it less likely that the hurricane will ever make landfall. The retreat of Arctic sea ice may someday make it possible to open a shipping lane through the Arctic Ocean. Scientists theorize that climate change has been accelerated by increased levels of carbon dioxide in the atmosphere. Many plants, including crops such as cotton, soybeans, wheat, and rice, can benefit from the increase in CO2. They can absorb the CO2 and yield more at harvest time as a result. On the other hand, in warmer weather crops may also be more at risk from insect pests and from severe storms or droughts.

Unanswered Questions

Scientists have little doubt that Earth’s climate is changing. It is impossible to predict exactly how any ecosystem will be affected by climate change. However, biologists and climatologists are collecting data about processes including solar radiation, precipitation, evaporation, the transfer of heat energy by winds and by ocean currents, and the ways in which plants affect climate. They interpret this information using computer models and try to answer questions about how global warming will affect Earth.

  • Could climate change alter certain ocean currents, changing Earth’s temperatures further?
  • How quickly might the polar ice caps melt?
  • How have global climate changes affected Earth’s ecosystems in the past?
  • Is there a way to preserve biodiversity on mountain tops and polar areas where animals and plants have no cooler places to migrate to?

UPDATES: Straight from the Headlines

Deep Sea Sediment Coring

Analyzing ocean floor sediments can provide scientists with data about how plants and animals were affected during past climate changes. The process of collecting deep sea sediments is expensive and time-consuming, but the results of this research give scientists a look at what life in the oceans was like millions of years ago.

To study these ancient organisms, scientists need sediment samples that are hundreds of meters long. To obtain these, they must use drills similar to the drills used by the oil and gas industry. Taking these samples requires many hours and can be dangerous if the seas are rough or full of ice. Once scientists have obtained the cores, they first split the core in half lengthwise. One half is sampled for fossils of ancient organisms. This is the “working half.” The other half, the “archive half,” is saved and stored away so that future scientists who may develop other questions can have access to this difficult-to-obtain material.

By carefully dissecting the working half of the sample, scientists discover microscopic fossils of marine animals. Scientists know that these ancient animals were very sensitive to slight changes in temperature and chemistry. These microfossils can tell scientists how Earth’s climate has changed over millions of years.

Oceanographer in Action

Ruth Curry
Title: Oceanographer, Woods Hole Oceanographic Institution
Education: B.S., Geology, Brown University

For Ruth Curry, spending time on the ocean waves has nothing to do with surfing or vacationing. She spends her time studying the ocean currents that affect our lives each day. Ruth Curry is an oceanographer at the Woods Hole Oceanographic Institute, an organization of scientists who research and study how the ocean affects the global environment.

Curry’s research focuses on the North Atlantic circulation and the currents that carry warm waters from tropical regions northward. As these warm waters reach higher latitudes, they release heat that warms the air above them and warms the climate of western Europe. As warm water cools, its density increases and it sinks to the bottom of the ocean. There it begins a southward journey back to the tropics. This conveyor belt of water plays an important role in maintaining Earth’s climate. Normally, the salinity, or saltiness, of ocean water stays about the same. But changes in global temperatures are melting large sheets of ice in Greenland, which is introducing large amounts of fresh water into the ocean. This fresh water is diluting the ocean water, making it less salty. A decrease in salinity makes ocean waters less dense and prevents them from sinking to the bottom of the ocean. Eventually, the melting of ice sheets in Greenland could cause the North Atlantic currents to slow and eventually stop, leading to dramatic changes in the Northern Hemisphere’s climate.

Pandemics—Is the Next One on the Way?

Could one of these travelers be carrying a virus that causes the next pandemic?

Imagine that a new virus emerges and people have no immunity. There is no vaccine. If this were to happen, there could be mandatory travel restrictions, quarantines, and social distancing—including staying out of all crowded places. In the United States alone, such an outbreak could kill up to 2 million people. But how can such a virus emerge, and how can we prepare for it?

Pandemics

When a new virus emerges, it infects organisms that have not developed immunity, or resistance, to the virus. If a new virus infects humans, it may spread easily from person to person before a vaccine can be produced. A disease outbreak that affects large areas of the world and has a high fatality rate is called a pandemic. The disease is spread through infection—for example, by sneezing or coughing—to a great number of people, very quickly.

The 1918 flu pandemic killed about 50 million people worldwide.

The 1918 flu pandemic was the most devastating pandemic recorded in world history. This virus infected nearly one-fifth of the world’s population, killing about 50 million people worldwide. It spread mainly along global trade routes and with the movement of soldiers during World War I.

If a new and deadly disease emerges today, a carrier could travel around the world in 24 hours. Several million people travel internationally by plane every year, easily reaching their destinations before they show any symptoms of carrying a disease.

The “Perfect” Virus

Not every virus is well suited to cause massive human casualties. For many viruses, humans represent a dead-end infection because they cannot be passed from human to human. For other viruses, victims die too quickly for the virus to reproduce. Quarantines can contain this type of virus relatively easily.

What characteristics would make an emerging virus likely to cause a pandemic? The virus would need to be adapted to humans as hosts and easily spread through casual contact. Victims would also have to survive infection long enough without symptoms to go about their daily business and infect other people. Finally, the most deadly virus would mutate rapidly, foiling the attempts of scientists to develop a vaccine or a drug that targets it.

Diseases That Jump to New Species

A zoonosis is a disease that can jump between species. A virus that evolves the ability to jump from a nonhuman animal species to humans will spread very quickly in the human body, which has not yet developed defenses. If this virus exchanges genetic material with another human virus, the virus may become capable of spreading from person to person.

The swine flu pandemic was caused by the H1N1 virus that originated in pigs. In 2009, it was estimated that 22 million people were infected with the H1N1 virus! World health officials urged individuals to get vaccinated and educated people on its symptoms. A year later, the swine flu was declared officially contained.

Avian Flu H5N1

Perhaps the most familiar zoonosis is the avian flu virus. Sometimes called the bird flu, this virus normally infects wild birds such as ducks and geese as well as domestic birds such as chickens. Migrating birds can carry it to other continents.

Researchers have been tracking a form of avian flu called H5N1. Like other flu viruses, H5N1 mutates rapidly. Random mutations may or may not help the virus adapt to new host species. However, viruses can mutate in a faster, less random way. If an animal becomes infected with viruses from two different species at the same time, the viruses can exchange genetic information. If this happens, the avian flu can jump the species barrier, becoming a flu virus that can be transmitted from one human to another.

Unanswered Questions

Despite the danger that a new virus represents, no one knows how the virus may mutate or whether it will cause a pandemic. Some of the most important questions include the following:

    • How can vaccines be developed quickly enough to stop a disease that can spread in hours or days?
    • Can a broad-spectrum antiviral drug be developed that could target more than one flu virus?
    • What specific molecular factors allow a virus to jump from one species to another?

UPDATES: Straight from the Headlines

Dissecting a Virus

Flu virus

H1N1 influenza virus

Scientists have long debated how the genetic material of influenza A viruses, RNA, is likely arranged. In 2005 virologist Yoshihiro Kawaoka and his team of researchers at the University of Wisconsin unraveled the mystery using a technique called electron tomography. Electron tomography is a way to construct a three-dimensional image from a series of electron microscope images taken at different angles. By making slices along flu virus particles that cut them into “top” and “bottom” halves,
researchers found that all influenza A viruses have a total of eight RNA strands. As shown at the right, seven strands form a circle just inside the edge of the virus particle, surrounding an eighth strand in the center.

Based on this similarity in structure, the researchers concluded that all influenza A viruses must share a specific mechanism for packaging their genetic material. This knowledge may make it possible to engineer viruses that can be used to mass produce vaccines to defend against these viruses, which are
responsible for regular seasonal outbreaks as well as the avian flu.

Epidemiologist in Action

Dr. Ben Muneta
Title: Medical Epidemiologist, Indian
Health Service
Education: M.D., Stanford University

In 1993, a mystery disease began to kill people in the southwestern United States. One of the experts that the Centers for Disease Control (CDC) consulted was Dr. Ben Muneta. Dr. Muneta is an epidemiologist, a scientist who studies the causes, transmission, and control of diseases within a population. He works at the Indian Health Service National Epidemiology
Program in Albuquerque, New Mexico.

Dr. Muneta consulted a traditional Navajo healer. From him, Dr. Muneta learned that the disease was associated with extra rainfall, which had caused the pinon trees to produce more nuts than usual. This in turn had led to a population explosion among mice that feed on these nuts.

Using this lead, CDC researchers determined that the disease was caused by hantavirus, a virus spread through the droppings of deer mice. With further research, Dr. Muneta confirmed that some Navajo healers had even predicted the 1993 outbreak.

Genetically Modified Foods—Do Potential Problems Outweigh Benefits?

can of genetically modified tomatoes

Although these tomatoes are labeled, genetically modified foods are not required to be labeled in the United States. However, they must meet the same standards of safety as traditionally grown food.

There is a food fight going on, and you may need to choose a side. Genetically
modified (GM) foods have been on the market since the early 1990s. Today most foods in the United States have GM ingredients. But the wide availability of GM food raises concerns about its effects on our health and on the environment. Should we continue to use GM foods?

New Technology, Old Idea

GM plants have genes that have been artificially introduced into the plant’s genome. This technology gives plants a new characteristic, such as a new color or different flavor. To date, most genetically engineered foods have been bred for disease resistance. GM crops on the market include wheat, rice, corn, soybeans, potatoes, tomatoes, and cantaloupes.

Genetic engineering is a fairly new process, but plants have been modified through careful selection and cross-breeding for thousands of years. In fact, many experts argue that genetic engineering of crops is just a faster and more precise method of selective breeding.

The Green Revolution

In the 1960s, scientist Norman Borlaug and a team of researchers used cross-breeding techniques to develop a new strain of wheat. The new strain produced two to three times as much wheat as traditional varieties, and resisted many types of insects and diseases. Widely planted, these new varieties changed Mexico from an importer of wheat to an exporter within 20 years. Borlaug and his team began shipping the new strain of wheat to India and Pakistan. Both countries quickly doubled their wheat production. This scientific advance, led by Borlaug, became known as the Green Revolution and drastically improved crop yields worldwide. For his work, Borlaug received the Nobel Prize in 1970. Borlaug supported the genetic engineering of crops and viewed it as the next wave of the Green Revolution.

Benefits of GM Crops

GM crops have the potential to improve nutrition worldwide. For example, researchers have developed a GM variety of rice, called “golden rice,” that is high in vitamin A. Half of the world’s population relies on rice as the main part of their diet. Non-modified rice lacks vitamin A, however, and vitamin A deficiency in humans can cause blindness and sometimes death. Golden rice could prevent millions of deaths of young children in developing countries every year. Other promising uses of genetic engineering include growing fruits and vegetables that produce vaccines in their tissues. Carrying important vaccines in food might eventually make shipment, storage, and administration of medicine easier worldwide.

GM crops benefit farmers because they take less time, water, and land to grow. Some GM plants can grow in poor soils or withstand drought, cold temperature, and insect damage. These crops lessen the need for pesticide, herbicide, or fertilizer. Consumers benefit from GM produce that stays fresh longer.

Potential Hidden Costs of GM Crops

biotech protestors

Some people worry that genetically-modified foods will negatlively affect ecosystems.

Opponents of genetically modified foods argue that it is impossible to predict exactly how the new crops—sometimes called “Frankenfoods”—will affect ecosystems. Two major concerns are herbicide-resistant weeds and pesticide-resistant pests, which create new ecological problems.

When herbicide-resistance genes are inserted into crop plants, the weeds are easily killed by herbicides while the crops remain unaffected. But pollen from plants can be carried by the wind for long distances, and seeds from GM crops could be accidentally dispersed outside their intended locations, causing the rise of “superweeds.” In the 1990s, several companies produced crops that were resistant to the herbicide Roundup. However, many weeds, such as pigweed, soon evolved resistance to Roundup. Pigweed can grow as much as three inches per day. It chokes out farm machinery and smothers crops. GM plants with the bacterial gene Bt produce an insecticidal toxin that is harmless to people. However, insects that evolve resistance will reproduce, increasing the population of pesticide-resistant pests.

Unanswered Questions

Genetically modified crops are no longer considered new, but some questions about them remain. Many of the most important research questions concern the long-term effects of GM crops on human health and the environment. Specific questions include

  • Will vitamin levels in genetically modified crops differ from those in their traditional relatives?
  • Could GM crops, such as those engineered to produce medicines, have adverse effects on wildlife?

UPDATES: Straight from the Headlines

Gene Gun

Genetic engineers use various ways to insert new genes into host cells. For plant cells, which have thick cell walls, one of the best ways to put foreign DNA into the cell is to actually shoot it through the plant tissue using a gene gun.

  1. A researcher coats gold or tungsten particles with DNA and places them on the end of a microscopic plastic bullet.
  2. The plastic bullet is placed in the gene gun and directed toward the target plant tissue.
  3. A burst of helium propels the bullet to the end of the gun. The gold particles containing the DNA are released, while the bullet remains in the gun.
  4. Particles enter the cytoplasm of some of the cells in the target tissue. DNA is released from the gold particles and moves into the plant cell’s nucleus, where it ultimately combines with the cell’s DNA.

Research Engineer in Action

Dr. Tong-Jen Fu
Title: Research Engineer, Food and Drug Administration
Education: Ph.D., Chemical Engineering, Pennsylvania State University

Dr. Tong-Jen Fu is a research engineer with the U.S. Food and Drug Administration (FDA), where she evaluates the methods currently used by scientists to determine the allergic potential of GM foods. She and other researchers are trying to understand exactly what makes substances in food cause allergic reactions.

One of the concerns of GM food is its potential to increase allergies in humans. Many proteins can potentially be an allergen—that is, cause an allergic reaction in some people. Since genetic engineering introduces new proteins into crops, concerns have been raised that unexpected allergies may arise. GM foods could trigger allergies by including proteins already known to cause a reaction, or by introducing completely new allergy-causing proteins—such as those from bacteria—into the food supply.

Researchers use extensive safety tests to determine whether a genetically modified food is likely to cause an allergic reaction. If any of these tests has a positive reaction, the GM food is not likely to be commercially produced. These tests include checking the amino acid sequences of introduced proteins against those of known allergens and testing whether the introduced proteins are resistant to digestion.

The Loss of Biodiversity

emperor tamarin

Emperor tamarins are omnivores that eat fruits, insects, flowers and nectar. As seed dispersers for a variety of plant species, these primates are important to the health of the tropical rain forest ecosystems in which they live.

Extinction is occurring at its fastest rate in the last 100,000 years. As humans develop land for agriculture and other human needs, ecosystems are changed. Each time an acre of land is lost, species that once lived there may be lost as well. Rain forests, for example, are areas with high biodiversity, and wide swaths are being destroyed by humans. Why is biodiversity important? How does its loss affect you?

Biodiversity at Risk

Biologists estimate that there are between 10 and 100 million species living on Earth. At current rates of extinction, over half of these species will be gone by the end of this century. Across the globe, animal species that are threatened with extinction include

  • 12 percent of all birds
  • 21 percent of all mammals
  • 28 percent of all reptiles
  • 30 percent of all amphibians
  • 70 percent of all plants

Extinction is a natural process and is always occurring. Using evidence from the fossil record, the
background extinction rate is calculated to be between 10 and 100 species per year. However, the
current rate of extinction greatly exceeds that number; we lose a species every 20 minutes! Hundreds of thousands of species will disappear before we are even aware of their existence.

The Value of Biodiversity

Ecosystems provide human communities with a number of services free of charge, including air and water purification, flood and drought control, pollination of crops and other vegetation, dispersal of seeds, and nutrient cycling. These services have an economic value. If humans had to pay for ecosystem services based on their market value, biologists estimate that the cost would be approximately $33 trillion annually.

In addition, 40 percent of all medicines are derived from plants, animals, and microbes. For example, biologists are developing a painkiller based on an extract from the skin of an Ecuadorian frog. The painkiller is 200 times stronger than morphine, but is not addictive. Every time a plant, animal, or microbe becomes extinct, biologists lose whatever knowledge they might have been able to gain by studying it.

Does Biodiversity Really Matter?

Some people might suggest that biodiversity belongs in a zoo and the rest of the world belongs to humans to develop. Arguments in favor of development include the following:

  • The rise and fall of species is part of nature. No species lives forever. New species replace old ones.
  • Economic development provides jobs to people who are living in poverty.
  • Land set aside as wilderness could be better used as farmland to provide more food for a rapidly
    increasing human population.

Conservation biologists view the pro-development arguments as shortsighted. Their view is that the Earth must be maintained for future generations, not simply harvested to provide for the needs of its
current population. In fact, they argue that biodiversity plays an important part in ecosystem stability.

In general, the more species that live in an ecosystem, the more efficient and stable that ecosystem will be. For example, a rain forest can produce much more oxygen than an orchard full of apple trees. Also, many plants, including 75 percent of the world’s staple crop plants, need animal pollinators such as birds and insects to help them reproduce.

Unanswered Questions

As you have learned, biodiversity is very valuable. Yet questions remain about how best to protect biodiversity. Two of these unanswered questions include

  • How can we slow down the current extinction rate?
  • Some of the areas with the highest amount of biodiversity are located in developing countries. How can biodiversity be preserved without harming the country’s economic growth?

UPDATES: Straight from the Headlines

Clean-up crews use the Pseudomonas putida bacteria (inset) to decontaminate soil polluted by oil spills. (colored SEM: magnification 300x)

Bioremediation

Microorganisms can be used to clean up wastes that are spilled. Some bacteria can eat substances that would be fatal to humans and most other animals. Using microorganisms to clean up a polluted environment is called bioremediation.

  1. Toxic waste, such as crude oil, is spilled on soil or in water.
  2. The waste kills most bacteria, but a few survive and adapt.
  3. Surviving bacteria feed on the toxins that were spilled and break them down. They may change the toxin to another form that is not dangerous, break the compound into smaller parts, or completely degrade it into inorganic molecules such as carbon dioxide and water.
  4. Oxygen and nutrients are added so that more bacteria will survive to help break down the toxins.
  5. When the spill has been completely broken down, bacteria die because they have run out of food.

Sometimes the needed microbes do not naturally occur in the contaminated site. When this is the case, the clean-up crew adds the specialized microbes to the site to break down the toxins.

Conservation Biologist in Action

Angel MontoyaAngel Montoya
Title: Senior Field Biologist, The Peregrine Fund
Education M.S., Wildlife Science, New Mexico State University

In 1990, Angel Montoya was a student intern working at Laguna Atascosa National Wildlife Refuge in Texas. He became interested in the Aplomado falcon, a bird of prey that disappeared from the southwestern United States during the first half of the 20th century. Montoya decided to go looking for the raptors, and he found a population of Aplomados in Chihuahua, Mexico. His work helped to make it possible for the falcons to be reintroduced to an area near El Paso, Texas.

Restoration of the Aplomado falcon became Montoya’s life work. He has monitored and researched the falcon since 1992. He helps release falcons that have been raised in captivity back into the wild, and monitors falcons that have already been released. It isn’t easy to keep tabs on a falcon, however. “Their first year they are pretty vulnerable because they haven’t had parents,” Montoya says. “Just like juveniles, they’re always getting into trouble. But I think they will do just fine.”

Brain Science—We Are Wired to Learn!

A six-month-old child watches a television, while an electrode hat measures the child’s brain activity. (Credit: Cary Wolinsky/National Geographic Image Collection)

Your brain has more than 100 billion cells, called neurons. Together, the neurons in your brain are so powerful that they can process more information than the most powerful existing computer can in the same amount of time. Your brain can accomplish so much because you’ve spent years—every second of your life—learning from and interpreting the world around you.

Plasticity of the Brain

What factors affect the brain’s plasticity, or ability to learn new things? How does the brain change with age? Neuroscientists have been addressing these questions since the early years of brain research.

During the first three years of life, the neurons in the brain rapidly form connections, or synapses, between each other. Neurons and synapses are overproduced in babies’ brains because their brains are taking in a lot of new information. At three years old, the brain begins to prune, or reduce the number of, these connections so that only the most used connections are intact. On average, three-year-olds have two times more synapses than adults have.

The brain does not lose all of its plasticity after the age of three. Even adults can learn a new skill, such as speaking a foreign language. Neuroscientists have found a second wave of brain growth and plasticity similar to that observed in infants, that begins just before puberty. During the teenage years, an intense period of pruning and strengthening begins and continues until the person is about 30. Connections that are used least are pruned away, and connections that are used the most are strengthened.

So how teenagers spend their time can affect their brain’s wiring. A teen violinist who stops practicing will see his or her musical skill fade. One researcher says, “If a teen is doing music or sports or academics, those are the cells and connections that will be hard-wired. If they’re lying on the couch or playing video games . . . those are the connections that are going to survive.”

Although researchers agree that playing video games affects the brain, they do not agree on how the brain is affected. Some studies suggest that video games could strengthen beneficial connections. Other studies imply that some beneficial connections could become weakened.

The Multitasking Brain

How might video games strengthen connections in your brain? Some video games present the player with complicated puzzles and patterns. The player must take in visual messages from the video screen while using problem-solving skills to analyze patterns. This multitasking requires the player to use different areas of the brain at the same time. Using language has a similar effect on the brain as playing video games in that both activate many areas of the brain at the same time.

For example, when you have a conversation with a friend, many areas of the brain become active. When you hear what your friend says, the brain area above your ear becomes active. When you form a response and speak, different brain areas become activated. The front of the brain is activated when you interpret your friend’s words and form a response. When you begin to respond, an area in the back of the brain becomes active. This area becomes more and more active as you talk.

Reading is another complicated activity. The same areas of your brain that are active when you talk to your friend are active when you read. But another area is also activated. This third area is farther back in the brain. It allows you to see and interpret the printed words in front of you. Even people who read Braille use the visual part of their brain to interpret what is on the page.

Unanswered Questions

Every new discovery in neuroscience brings with it new questions. Some of these include the following:

  • Can the plasticity of an adult brain be used to help adults recover from brain injuries and diseases?
  • Can neuroscientists find ways to treat, or even cure, disorders such as Alzheimer’s disease?
  • Why are humans, and not other primates, good at learning words and systems of grammar?

UPDATES: Straight from the Headlines

Scanning the Brain

MRI testing

MRI testing (Credit: Francesco Ruggeri/Photographer’s Choice/Getty Images)

Much of today’s research on brain function uses functional magnetic resonance imaging (fMRI). In a traditional MRI, computers use information from a magnetic field to make a three-dimensional cross-sectional image of the brain. An fMRI uses an MRI machine to detect the areas of the brain that are receiving the most oxygenated blood. Computer software analyzes this data to determine which part of the brain is active while a person performs different tasks, such as reading, listening to music, doing math, or even receiving medical treatment.

MRIs and fMRIs, though, are expensive and cumbersome, making it impractical to do brain imaging studies on large groups of people. Some researchers are now experimenting with using portable, weak lasers to scan the brain. This technique is called functional near-infrared spectroscopy, or fNIRS. The weak lasers used in fNIRS can measure changes in blood flow in the front part of the brain. Because it is the size of a headband and easily portable, researchers have used fNIRS to study blood flow to the brain in extreme environments, such as in parabolic flight.

Late in 2010, scientists at the University of Texas in Dallas and Arlington presented a new invention that can take images of a brain without a person’s hair getting in the way: a laser hairbrush. Called “the hairbrush that reads your mind,” the “brush optrode” slides laser fibers between hair follicles, getting an
optical signal that is three to five times stronger than can be generated on the same head by a fNIRS headband.

Neuroscientist in Action

Dr. Rae Nishi
Title: Director, Neuroscience Graduate Program, University of Vermont
Education: Ph. D., Biology, University of California, San Diego

Dr. Rae Nishi’s research proves that you do not need complicated technology, such as fMRIs, to make discoveries in neuroscience. Through observation and experiment, Dr. Nishi’s research tries to answer the question: What causes brain cells to die?

Although the question is too broad to answer completely, Dr. Nishi has discovered a molecule that
seems to keep alive brain cells in dying chick embryos. She also found that by blocking a certain receptor on the surface of neurons, dying neurons will stop showing signs of decline. Studies of how and why brain cells might die are important in understanding Alzheimer’s and Parkinson’s diseases, which cause certain areas of the brain to become inactive.

“There is no profession as exciting as being a scientist,” Dr. Nishi says. “You get to learn new things
every day. You get to make discoveries. You get to solve puzzles.” Dr. Nishi is currently working to
determine how the molecules released during one neuron’s death might trigger the growth of new, neighboring neurons.