11.P bo's team, which has been sequencing Neanderthal DNA, continually faces these problems."When you want to study ancient human and Neanderthal remains, there's a big issue of contamination with contemporary human DNA," he says.
12.This doesn't mean that all museum specimens are fatally flawed, notes P bo.The Neanderthal fossils that were recently sequenced in his own lab, for example, had been part of a museum collection treated in the traditional way.But P bo is keen to see samples of fossils from every major find preserved in line with Geigl's recommendations — just in case.
Warm and wet
13.Geigl herself believes that, with cooperation between bench and field researchers, preserving fossils properly could open up avenues of discovery that have long been assumed closed.
14.Much human cultural development took place in temperate regions.DNA does not survive well in warm environments in the first place, and can vanish when fossils are washed and treated.For this reason, Geigl says, most ancient DNA studies have been done on permafrost samples, such as the woolly mammoth, or on remains sheltered from the elements in cold caves — including cave bear and Neanderthal fossils.
15.Better conservation methods, and a focus on fresh fossils, could boost DNA extraction from more delicate specimens, says Geigl.And that could shed more light on the story of human evolution.
(640 words nature )
Glossary
Palaeontologists 古生物学家
Aurochs 欧洲野牛
Neanderthal (人类学)尼安德特人，旧石器时代的古人类。
Permafrost (地理)永冻层
