Ancient fossil specimens of extinct species are genetically more distant to an outgroup than extant sister species are.

ABSTRACT: There exists a remarkable correlation between genetic distance as measured by protein or DNA dissimilarity and time of species divergence as inferred from fossil records. This observation has provoked the molecular clock hypothesis. However, data inconsistent with the hypothesis have steadily accumulated in recent years from studies of extant organisms. Here the published DNA and protein sequences from ancient fossil specimens were examined to see if they would support the molecular clock hypothesis. The hypothesis predicts that ancient specimens cannot be genetically more distant to an outgroup than extant sister species are. Also, two distinct ancient specimens cannot be genetically more distant than their extant sister species are. The findings here do not conform to these predictions.

SUBMITTER: Huang S 

PROVIDER: S-EPMC2649772 | biostudies-literature | 2008 Jan-Apr

REPOSITORIES: biostudies-literature