Ancient DNA--When Is Old Too Old?

The 1997 resurrection of a snippet of Neandertal mitochondrial DNA electrified human paleontology and attracted wide media attention.1 By comparing the number of base changes in that Neandertal sample to variability in modern humans, scientists concluded that a common African ancestor existed about 600,000 years ago, far earlier than the generally accepted origin of modern humans about 150,000 years ago. And while Neandertals were still around as late as 30,000 years ago, it's unlikely that mod

Barry Palevitz
Jul 18, 1999

The 1997 resurrection of a snippet of Neandertal mitochondrial DNA electrified human paleontology and attracted wide media attention.1 By comparing the number of base changes in that Neandertal sample to variability in modern humans, scientists concluded that a common African ancestor existed about 600,000 years ago, far earlier than the generally accepted origin of modern humans about 150,000 years ago. And while Neandertals were still around as late as 30,000 years ago, it's unlikely that modern humans cavorted in the same gene pool.

Using ancient DNA to illuminate the past fascinates biologists. The Spring 1999 newsletter of the National Center for Biotechnology Information (NCBI) lists 14 ancient sequences registered with GenBank, including fragments from an Egyptian mummy, the Tyrolean "iceman," a Siberian woolly mammoth, the extinct zebralike quagga, and a tinsel-town saber-toothed tiger.2 David Wheeler, who surveyed NCBI's holdings for the article, actually turned up 37 such...