Genes in common

Illustration of chimps swinging from a DNA strand Fall 2015

Jane Goodall’s observations of chimps in Gombe Stream National Park revealed that they use tools, eat meat and make war. Now, School of Medicine scientists have discovered that some of the Tanzanian primates may resist the disease progression of SIV, the simian equivalent of HIV, for the same reason some humans do.

Humans who have a particular variant of HLA-B, a gene that codes for proteins that help the immune system recognize invaders, resist progression from HIV to AIDS. Some of the Gombe chimps have an analogous variant, a portion of which strongly resembles the human one — and infected chimps with the variant have lower fecal counts of SIV than infected chimps without.

The similarity of part of the chimp and human variants implies two things, says Peter Parham, PhD, professor of structural biology and of microbiology and immunology.

First, hominids have been fighting off HIV-like viruses at least since the two species diverged some 5 million years ago. Second, because that particular section of the gene variant hasn’t changed much since then, it probably plays an important role in increased survival among those inheriting it.

Parham is the senior author of the study, published online in May 2015 in PLOS Biology. The work could lead to drugs or gene therapy to help people with HIV avoid progressing to AIDS.