With advances in molecular biology and genomics, researchers can draw more and more information out of old, preserved samples, says The Washington Post. While some researchers focus on very old samples — like those from Neanderthals — other researchers are looking at the more recent past. The US National Institutes of Health's Jeffery Taubenberger has been studying the 1918 pandemic flu virus — the eight genes of which were reconstructed from a number of preserved tissues — and an earlier, springtime version of the virus that wasn't as devastating. Other researchers, like the University of Arizona's Michael Worobey, are tracing the lineage of HIV to determine when it first entered the human population — Worobey found HIV genes in tissue samples taken from a woman in the Congo in 1960.
Of course, the samples are limited and, thus, precious. "We could easily burn up all the material just trying to find out what subtype [of flu] we have," Taubenberger tells the Post. "I have been very reluctant to just dive in. We have waited 110 years, and we can wait a little longer."