Bonobos show limited genetic variation in intron 2 of MHC class I
18 August 2017
MHC class I molecules play a central role in the defense of viruses. The study of the DNA that encodes the MHC can teach us a lot about the effects of pathogens on our immune system.
Previously it was shown that chimpanzees contain far fewer MHC class I variants than humans. BPRC researchers found that the chimpanzee MHC molecules shared functional similarities with certain human MHC molecules associated with controlling the AIDS virus (HIV-1). Chimpanzees are able to control the monkey AIDS virus (SIVcpz) as well as infections with HIV-1. It therefore appears that the chimpanzee MHC has gone through a bottle neck during evolution (https://link.springer.com/article/10.1007%2Fs00251-017-1006-6). The current chimpanzee population therefore possess MHC variants that protect against these types of viruses.
Bonobos are closely related to chimpanzees and share a joint ancestor about 1.5-2 million years ago. The researchers have now studied in more detail whether or not bonobos also have limited variation in the MHC class I. To this end, they have compared the variation in intron 2 of the bonobo MHC genes to that of humans and chimpanzees. It was found that the MHC genes of bonobos contain even less intron 2 variants than chimpanzees. This suggests that the selection in the MHC, described for chimpanzees, has already taken place in the ancestors of bonobos and chimpanzees. This work has been published in the Immunogenetics magazine (https://link.springer.com/article/10.1007%2Fs00251-017-1010-x).