The team hope their work will pave the way to new treatments
Scientists say they have decoded the entire genetic structure of HIV-1 - the main cause of Aids in humans.
They hope this will pave the way to a greater understanding of how the virus operates, and potentially accelerate the development of drug treatments.
HIV carries its genetic information in more complicated structures than some other viruses.
The US research, published in Nature, may allow scientists the chance to look at the information buried inside.
HIV, like the viruses which cause influenza, hepatitis C and polio, carries its genetic information as single-stranded RNA rather than double-stranded DNA.
The information enclosed in DNA is encoded in a relatively simple way, but in RNA this is more complex.
RNA is able to fold into intricate patterns and structures. Therefore decoding a full genome opens up genetic information that was not previously accessible, and may hold answers to why the virus acts as it does.
The team from the University of North Carolina at Chapel Hill said they planned to use the information to see if they could make tiny changes to the virus.
"If it doesn't grow as well when you disrupt the virus with mutations, then you know you've mutated or affected something that was important to the virus," says Ron Swanstrom, professor of microbiology and immunology.
"We are also beginning to understand tricks the genome uses to help the virus escape detection by the human host."
Dr David Robertson from the University of Manchester welcomed this "definitive analysis".
"What this may reveal is some of the functions operating at a level below protein structures, which may have all sorts of importance for the virus."
"More generally, if we can understand these RNA structures then we can compare the systems of different viruses and gain new understanding of their role in virus biology."
Keith Alcorn of the HIV information service NAM added: "Encouraging the virus to mutate is not a new idea, but it is one of a number of options on the table.
"How important this information will be for the development of new drugs remains to be seen, but it is a useful addition to what we know."