The San Jose Mercury News is reporting today on a Stanford study showing that the same gene variants that can lead to certain diseases today may have actually protected humans from more deadly ailments in the past.
As Lisa Krieger explains, scientists have long wondered why humans haven't evolved to become less susceptible to complex disorders like Type 1 diabetes and rheumatoid arthritis. For this study, researchers studied gene sequences derived from a 17,000-person database in England and found that the gene variants that cause these ailments appeared to have "shield[ed] our forebears from a bigger killer: infectious disease." From her article:
"When a child is diagnosed, parents ask: Why is this in our genes?" said [Atul Butte, MD, PhD] assistant professor of pediatric cancer biology and a bioinformatics expert at Stanford's Lucile Packard Children's Hospital.
"Now we have an answer," he said. "It is in our genes because at one point in human history, these genetic variants were protective against viruses and bacteria."
In a release, Butte said he and his colleagues are expanding their investigation to include more diseases and focusing on the genetic profile of certain tumors:
“Even though we’ve been finding more and more genetic contributions to disease risk,” said Butte, “that’s not really an appealing answer. There have got to be some other reasons why we have these conditions.”