Neanderthal genes: What do they mean?

✍ Scribed by Ian Tattersall

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 37 KB
• Volume: 6
• Category: Article
• ISSN: 1060-1538
• DOI: 10.1002/(sici)1520-6505(1998)6:5<157::aid-evan3>3.0.co;2-9

✦ Synopsis

T he recent sequencing by Krings and coworkers 1 of 378 bp of Neanderthal mtDNA undoubtedly marks a major technological advance for paleoanthropology. Extracted from a bone sample from the original Feldhofer Cave Neanderthal specimen and representing the hypervariable region 1 of the Neanderthal mitochondrial genome, this short sequence, when compared with a modern human reference sequence, showed 24 transition mutations, 2 transversions, and 1 single nucleotide insertion. The same DNA region averages only 8 substitutions among modern human individuals. Significantly, the differences between Neanderthal and modern humans were identified at sites with a strong tendency to vary in comparisons between modern human and chimpanzee sequences. 2 The average number of differences separating the Neanderthal and human sequences was thus about three times that among modern human individuals and about half the number separating modern humans and chimpanzees. 1 Krings and colleagues also found that in quantitative phylogenetic analyses the Neanderthal sample invariably appeared as the outgroup of all modern human populations. They estimated a divergence time for the Neanderthal and modern lineages of 550 to 690 kyr, in contrast to an age of 120 to 150 kyr for the ancestor of modern human mtDNAs. These authors concluded that their data support the notion that ''modern humans arose recently in Africa as a distinct species and replaced Neanderthals with little or no interbreeding'' (p. 27).

These findings have received a lot of attention in the popular press and elsewhere, but I am unaware of any substantive criticism of the technical aspects of the study, which was very tightly controlled. Naturally enough, however, the authors' phylogenetic