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quote:Originally posted by TitanscapeAids was originaly a disease in African monkeys which were used to make vaccinations for people in Africa. However there was cross species contamination. The monkeys used, the vaccinations and the area of Aids origin coincides.
quote:The timescale of evolution inferred from viralMOLECULAR CLOCKS also seems incompatible with longtermco-divergence. If co-divergence were true, thenthe divergence times of SIVs should broadly matchthose of their hosts, going back millions of years.However, all molecular clock estimates of primatelentivirus evolution are orders of magnitude morerecent than this14, and the rates of mutation and replicationare similar among these viruses15,16. Therefore, ifmolecular clocks are accurate, then the evolutionarytimescale for each epidemic of HIV-1 and HIV-2 ismeasured only in decades. Several methods are availableto measure substitution rates, and thereforedivergence times, in RNA viruses, although the mostreliable estimates come from analysing the temporaldistribution of nodes on trees (BOX 2). Application ofthese (and similar) methods have led to suggestionsthat the M group of HIV-1 originated in the 1930s,with a range of ~10 years on either side17–19 (but seeBOX 2). A broadly similar evolutionary timescale hasbeen proposed for HIV-2 (REF. 20).Although most estimates for the time of origin ofHIV-1 are consistent, all can be subject to the same systematicbias. Once again, recombination might contributeto this error.Recombination has complex effectson the estimation of divergence times, by increasingapparent variation in rates among nucleotide sites andreducing genetic distances between sequences21,22. Inthese circumstances, perhaps the only reliable indicatorsof the timescale of HIV evolution are archival viral samples.The earliest HIV-1 M group sequence that is availablewas sampled in the Democratic Republic of Congoin 1959 (REF. 23). That this sequence falls some distancefrom the root of the M group tree is strong evidencethat the diversification of these viruses occurred beforethis time (BOX 2).Accurately dating HIV evolution willrequire the analysis of more such ‘fossil’ viruses.
quote:Originally posted by VAlibrarianOkay, I must venture opinions on this thread.First, the HIV organism did probably penetrate humans around that 1950s time in my view. How? No need to stipulate anal sex with monkeys, that is just silly. The facts are that monkess and Chimpanzees are hunted for food extensively (many species now face extinction due to this) in Africa, and in one or much such episode, it is likely that a bite or a cut allowed the infected blood to pass between the two species. Not very different from the Chicken farmers in Thailand and Turkey who recently died from coming into contact with the H5N1 flu from their chickens. The human hunter then was able to pass it on through sexual contacts (it is also silly to call HIV a homosexual disease at this point, after many millions of Africans have died from getting it heterosexually). A disease like HIV can be invisible in a place like Africa for a long time, because in Africa there are many obscure slow acting diseases. So we became conscious of it in the 1980s when thousands of Americans were becoming ill- and when French researchers finally were able to identify the virus. Conspiracy theories are not necesary to explain the awesome destructive power of HIV. Such theories only serve to make us falsely feel safer or provide somebody to "blame" for the existence of a microbe. It just happened, get over it. The real question now is how to change our behaviors so that we can keep prevent another 40 million people from contracting it.chris wiegard