These stories describe NIGMS-funded medical research projects. Although only the lead scientists are named, they work together in teams to do this research.
You may be surprised at how little human DNA differs from that of the great apes. Chimps, our closest living relatives, share perfect identity with 96 percent of our genome.
But chimps are unlike us in many ways besides being furry and really loving bananas: They do not get AIDS, many cancers or deadly malaria.
Can evolution explain the differences and help us combat killer diseases?
Yes, says evolutionary biologist Ajit Varki of the University of California, San Diego. He discovered that chimps—but not people—produce the natural glycan molecule "Gc." Glycans are essential body sugar molecules that can also attract disease-causing microbes.
But Varki also found that many people have Gc in their bodies and anti-Gc antibodies in their blood. He thinks that people are exposed to Gc by consuming red meat and milk, two rich sources of the glycan.
An evolutionary change that dropped a Gc-producing enzyme from human DNA may now put us at risk, Varki guesses. He is investigating whether the human immune reaction against Gc may spur some cancers and infectious diseases. —Alison Davis
Malaria, caused by infection with parasite-infected mosquitoes, is rampant in Africa.
The disease also devastates populations in Latin America and Asia, but the parasite culprit in these other regions, called P. vivax, differs from the African parasite in many ways.
Although P. vivax rarely kills, it does cause severe illness. And because it can lie dormant in the body for many years, those infected could get malaria again—months or years later.
Until now, researchers knew very little about P. vivax because they could not get it to grow in the lab. Now, parasitologist Jane Carlton of the New York University Langone Medical Center and an international research team have broken new ground by cracking the parasite's genetic code.
Carlton and her team also compared the P. vivax genome with that of other malaria parasites and learned that P. vivax is unusual in many ways. She hopes that its evolutionary secrets will point to effective ways to control malaria or to eradicate the parasite in affected regions. -A.D.
Believe it or not, bacteria are not so bad—they actually play key roles in our health. Bacteria help us digest food, provide vitamins we can't make ourselves, and act as part of our immune defense.
To understand more about the role of bacteria on human skin, scientists need to know which ones are there and whether they differ much between people.
Geneticist Elizabeth Grice of the NIH in Bethesda, Md., took an inventory of skin bacteria from several healthy people. Grice collected bacteria by swabbing, scraping or cutting out a tiny piece of inner elbow skin.
After analyzing the genetic material in all the samples, Grice found a common subset of elbow skin microbes in all the people tested. But the bacteria were very different from those in the intestines and other skin areas of the same people, revealing an extraordinary diversity of life in and on our bodies.
The evolutionary question of how and why bacteria share our bodies is likely to be important for modern-day health. Altering the balance of skin bacteria, for example, may promote health and fight disease. —A.D.
In many ways, our DNA is like a fossil record, accumulating genetic changes due to lifestyle, climate and other shifts.
Geneticist Greg Gibson of North Carolina State University in Raleigh wanted to know more about how the environment we live in shapes our DNA.
He sampled blood from subgroups of Moroccan Amazighs in Northwest Africa and then measured the activity of several hundred genes. The Amazighs, while genetically similar as an ethnic group, live very different lives as subgroups. Some wander as nomads, while others have settled in the mountains or in coastal cities.
Gibson discovered that the activity of about one-third of the Amazigh white blood cell genes varied among the three subgroups, suggesting that environmental triggers cause genes to be read differently according to region.
Tracking the interplay between genes and the environment will be key to understanding how modern-day diseases gain a foothold, Gibson thinks. And intercepting these interactions may help researchers find new ways to steer clear of disease. -A.D.