This week, the pressures facing young scientists decades ago and today.

In many ways, there are perhaps more similarities than differences.

It was stressful then and it's stressful now.

And old virus samples confirm that HIV came early to the USA.

You can step back into the late 1970s to New York City and just see directly that this was already a very extensive mature epidemic.

Plus the genes that aren't quite genes, but still work kind of like genes.

This is the nature podcast for October the 27th, 2016.

I'm Adam Levy.

And I'm Kerry Smith.

Often, the best evidence of the history of a particular creature comes from ancient specimens,

bones, teeth, and impressions in stone. But it's not so simple when the creature you're tracking down is a virus as Kerry discovered.

Michael Warraby has been through a lot in the course of his research into the history of HIV.

He's been tracing the evolution of the virus which emerged in humans, having first developed in apes.

And it involves a lot of detective work. I've done work in the Congo, tracking down chimpanzees

and collecting their urine and feces to look for AIDS-related viruses and actually almost

died. I got a bad infection in my hand. For his latest project, he had to get samples from somewhere

even harder to reach. We've just gone back in time. The world became aware of HIV 35 years ago

when a short article appeared in a publication

called The Moridity and Mortality Weekly Report.

It was a summary of five case reports

from hospitals in Los Angeles.

All young homosexual men with a type of pneumonia

...