UC Berkeley
2013 Stories
Bottlenecks, BRCA, and Breast Cancer
As tests for genes that contribute to more diseases become available and, in many cases, become cheaper, we will increasingly be faced with decisions about how much we want to know about our future health prospects. Would you want to know if you carried a gene that conferred a 60% chance of developing Huntington’s disease by age 65? Or that multiplied your chances of having a stroke by five—even though the risk of having a stroke in any given year would still be extremely low? How much would you pay for a test that, for more than 99.5% of women will reassure them that nothing is wrong, but in the other cases will reveal that one’s odds of developing ovarian cancer are 39%? A prime example of this situation made the front page of the New York Times last month—and highlighted the deep connections that genetic testing has to the evolutionary history of human populations…
Read more »
Lumping or splitting in the fossil record
Rarely does pure science take top billing in the news, but this past month saw a notable exception. The front page of the New York Times was occupied by the image of an ancient hominid skull caked in dirt. This 1.8 million-year-old fossil, excavated in the Republic of Georgia, represents the oldest complete adult cranium of a hominid yet discovered. That alone would be significant news, but the context in which the fossil was preserved adds even more weight to the discovery…
Read more »
The legless lizards of LAX
Last month, biologists announced the discovery of four new species of lizard, not in an exotic tropical jungle, but right under our noses. The new-to-science animals (from the genus Anniella) were found at several unlikely locations — including in an abandoned lot in Bakersfield, California, and near the runway at Los Angeles International Airport. But don’t count on catching sight of one of these critters the next time you have a layover at LAX. First, they are small — less than 8 inches long. Second, they live mostly underground (the researchers had to tempt them out of hiding by leaving pieces of cardboard and plywood on the ground). And third, even if you did see one, you might not recognize it as a lizard. The four new species have no legs and could easily be mistaken for snakes! So why aren’t these sleek, scaled creatures snakes, and how did they avoid detection for so long? The answers are evolutionary ones …
Read more »
A new old animal
Eoperipatus totoro doesn’t look much like a fearsome predator. In fact, this two-inch long critter resembles nothing so much as a plush, candy-colored caterpillar with wriggly antennae. But this little known animal is no caterpillar. It is a velvet worm — a.k.a. an onychophoran, a group of organisms that today live in tropical regions and trap their insect prey using jets of sticky slime, a-la Spider-Man. Discovered in Vietnam and officially described just last month, this particular species may be new to science, but the onychophorans as a group have long been of interest to biologists for their important role in evolutionary history…
Read more »
Antibiotic resistant bacteria at the meat counter
The pork chops you buy in the supermarket neatly packaged in plastic and styrofoam may look completely sterile, but are, in fact, likely to be contaminated with disease-causing bacteria — and not with just any old bugs, but with hard-to-treat, antibiotic resistant strains. In a recently published study, researchers with the National Antimicrobial Resistance Monitoring System bought meat from a wide sampling of chain grocery stores across the country and analyzed the bacteria on the meat. Resistant microbes were found in 81% of ground turkey samples, 69% of pork chops, 55% of ground beef samples, and 39% of chicken parts. Of course, thoroughly cooking the meat will kill the germs, but if the meat is undercooked or contaminates other food with its bacteria — perhaps via a shared cutting board — the result could be an infection that can’t be cured with common medications. Such infections are a serious health concern — a strain of antibiotic resistant staph was recently estimated to cause nearly 20,000 deaths per year in the U.S. — and the problem seems to be getting worse. An evolutionary perspective helps us understand how antibiotic resistance arises in the first place and why the prevalence of resistant bugs in livestock has health professionals and scientists worried.
Read more »
No more mystery meat
Diners sitting down to enjoy a burger couldn’t be faulted for wondering, “Where’s the beef … from?” After all, just a few months ago, European consumers were dismayed to discover that many products marketed as beef actually contained large quantities of horse meat. Genetic fingerprinting, which was used to detect the imposter beef, can identify meat as a particular species or even a particular population. However, other analyses of genetic data can trace the source of a patty, McNugget, or filet, not just to a particular breed or population, but back in time. Using these techniques, scientists have uncovered the deep evolutionary origins of domesticated animals (such as sheep) and major crop plants (such as corn). Now, they’ve applied those techniques to cattle as well. This month, a team of researchers from the Universities of Texas and Missouri announced the results of a study focusing on the origins of breeds specific to the Americas, like the Texas Longhorn. The story told by the cows’ genes crisscrosses the trajectory of human evolutionary history — from wild aurochs that lived alongside Neanderthals, to Christopher Columbus and, ultimately, the American West …
Read more »
The recent roots of dental disease
Science has now provided an excuse for those of us used to being chided by our dentists for not brushing often enough: blame your cavities on the Industrial Revolution. New research suggests that the dietary changes associated with the Industrial Revolution 150 years ago (and with the invention of agriculture 10,000 years ago) caused an epidemic of tooth decay and gum disease. The culprits are oral bacteria. The human mouth is the native home of a wide variety of microbes, some helpful species and some harmful. Over the course of human history, eating more starch and sugar seems to have tipped the balance in favor of the disease-causing bacteria. Even without ultrasonic toothbrushes and mouthwashes, our ancestors may have had healthier teeth than we do!
Read more »
Influenza, an ever-evolving target for vaccine development
It’s that time of year again. Coughing coworkers, student absences, and reminders to get your shot are sure signs that flu season is upon us. This year’s epidemic seems to have struck earlier and harder than usual — all amid concerns over shortages of the flu vaccine. While some vaccines provide lifelong protection with one or a few doses (e.g., measles, mumps, and polio), the flu requires a new shot every year. And in some years, the flu shot is hardly effective at all. Why is the flu vaccine different from so many other vaccines? A look at the evolution of the flu virus can explain the weaknesses of current vaccines and points the way towards a vaccine that could provide long-lasting, universal protection.
Read more »