What origins for virus HIV1? What origins for virus HIV1?
This is the alignment of a small part of the POL protein of the HIV1 virus GenBank KU749412.1, with the POL protein of the Visna virus GenBank L06906.1
IKKKDSTKWRKLVDFRELNKRTQDFWEVQLGIPHPAGLKKKKSVTVLDVGDAYFSVPLDESFRKYTAFTI--PSTNNETPGIRYQYNVLPQGWKGSPAIFQSSMTKILEPFRAQNPEIVIYQYMDDLYVGSDLEIGQHRAKIEELREHLLRWGFTTPDKKHQKEPPF--------LWMGYELHPDKWTVQPIQLPE--KDSWTVNDIQKLV
|||| | ||| | ||||||| | |  | ||| ||| ||  || || || |||||  || |  | || |    |  ||  |  ||   ||||||| |||  |  | |||       | |    |||| | ||||  |      || |                                | |||| ||  |   |||      | |  ||||                 
IKKK-SGKWRMLIDFRELNKQTEDLAEAQLGLPHPGGLQRKKHVTILDIGDAYFTIPLYEPYRQYTCFTMLSP--NNLGPCVRYYWKVLPQGWKLSPAVYQFTMQKILRGWIEEHPMIQFGIYMDDIYIGSDL--GL-----EEHRGIVNELASYIAQYGFMLPEDKRQEGYPAKWL-GFELHPEKWKFQKHTLPEITEGPITLNKLQKLV

Are these matches,

By chance or,
HIV1 is a direct descendant of the Visna virus or,
they have a shared progenitor?

So it could also be that HIV1 really comes from some kind of experiment involving Visna virus, as I read on the Internet.
The disease caused by the Visna virus is (100% deadly see https://pubmed.ncbi.nlm.nih.gov/16425963/ ). Could there be parallels to sars2?
But look at it: the Visna virus is transmitted by air the first symptoms are like pneumonia (or a brain infection) and otherwise remains slowly progressing... like sars2, see long covid...
Symptoms are also felt after many days that the virus has come into action, this seems to me not to happen for coronaviruses or for flu viruses but for HIV and Visna virus
Link related:

https://pubmed.ncbi.nlm.nih.gov/8289690/

https://pubmed.ncbi.nlm.nih.gov/16425963/

(preprint sars2 as retrovirus) https://www.biorxiv.org/content/10.1101/2020.12.12.422516v1

https://www.gao.gov/assets/100/91319.html
They are both lentiviruses and share a distant common ancestor.
HIV-1 and HIV-2 are descendents from simian immunodeficiency virus (SIV). The following tree shows the relationships very clearly, from Wertheim and Worobey (2009) Dating the Age of the SIV Lineages That Gave Rise to HIV-1 and HIV-2 PLoS Comp Biol. here. The evolution of HIV-1 is heavily mixed with chimanpzee (cpz) SIV, and there are regions of highly anomalous homology juxtaposed with regions of notably lower homology.