Lecture 28 Flashcards
What did researchers do involving poop to show HIV came from chimpanzees?
SIV (simian immunodeficiancy virus) is the closest relative to HIV, this is found in chimpanzees and is the reason HIV is believed to be from chimpanzees. These have only been easily found in captive chimpanzees and as such it is important to get detection of SIV from non captive individuals, this can be done by detecting SIVcpz antibodies and nucleic acids in fecal samples (not blood, this is too difficult). Results from doing thisshowed 29-35% prevalence rates in some communities, establishing Pan troglodytes troglodytes (chimpanzee subspecies) from southern Cameroon as a natural reservoir of HIV-1 after sequencing of SIVcpz strains.
What are the four subspecies of chimpanzees in Africa based on mitochondrial DNA and how are they seperated?
The four subspecies of chimpanzees based on mitochondrial DNA are: Pan troglodytes verus (West Africa), P.t.vellerosus (NIgeria and northern Cameroon), P.t.troglodyte (Southern Cameroon, Gabon, and republic of Congo), P.t.schweinfurthii(democratic republic of Congo and countries to the east), these chimpanzee groups are seperated by large rivers and torrential rain.
How did the chimpanzee poop assay work?
Assaying the chimpanzee poop was done by checking for antibodies which react to particular parts of the HIV genome, primarily the chimps reacted to p24, though there were several other sites reacted to. RNA was also extracted from all immunoblot reactive samples and subjected to reverse transcription polymerase chain reaction amplification using consensus env (300 bp) and pol (800 bp) primers, this would mean amplification occured if the chimps had SIV. Sequences were amplified from 31 different P.t.troglodyte poop samples (about 16 apes).
What were the results of studying chimpanzee poop??
Results of studying chimpanzee poop showed prevalence rates from 4-35% depending on the site the poop was taken from. Phylogenetic analysis was done on the found SIVcpz strains and added to a genetic tree for comparison to other strains. This showed that some SIV strains were more similar to HIV-1 than other SIV strains, strains from the same poop site were more similar than with strains from different poop sites. M/A and M/B HIV-1 strains are most similar to the SIV from poop site MB and LB, the HIV-1 N (the less problem type) is more closely related to SIV from site EK.
What was the conclusion of studying chimpanzee poop?
HIV-1 groups M and N each resulted from independent cross-species transmissions of SIVcpzptt strains from different locations. The O group came from Gorilla poop.
