Going subacute.
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Continuity of Patient Care↗
Biomedical subjects
S Zehr
Publications and source records attributed to S Zehr.
Gene trees and hominoid phylogeny.
Here we present a DNA sequence study that incorporates intraspecific variation from all five genera of hominoids (apes and humans). Recently it has been claimed that using single individuals to analyze species' relationships might be misleading if within-species variation is great. Our results indicate that despite high intraspecific variation in mitochondrial cytochrome oxidase subunit II gene sequences of some hominoids, humans and chimpanzees are nonetheless significantly most closely related. We also report the observation that variation within the gorilla species exceeds that between common and pygmy chimpanzee species, a finding with implications for conservation. In contrast, humans are less mitochondrially diverse than lowland gorillas inhabiting western Africa.
Animals↗
Mitochondrial COII sequences and modern human origins.
The aim of this study is to measure human mitochondrial sequence variability in the relatively slowly evolving mitochondrial gene cytochrome oxidase subunit II (COII) and to estimate when the human common ancestral mitochondrial type existed. New COII gene sequences were determined for five humans (Homo sapiens), including some of the most mitochondrially divergent humans known; for two pygmy chimpanzees (Pan paniscus); and for a common chimpanzee (P. troglodytes). COII sequences were analyzed with those from another relatively slowly evolving mitochondrial region (ND4-5). From class 1 (third codon position) sequence data, a relative divergence date for the human mitochondrial ancestor is estimated as 1/27 th of the human-chimpanzee divergence time. If it is assumed that humans and chimpanzees diverged 6 Mya, this places a human mitochondrial ancestor at 222,000 years, significantly different from 1 Myr (the presumed time of an H. erectus emergence from Africa). The mean coalescent time estimated from all 1,580 sites of combined mitochondrial data, when a 6-Mya human-chimpanzee divergence is assumed, is 298,000 years, with 95% confidence interval of 129,000-536,000 years. Neither estimate is compatible with a 1-Myr-old human mitochondrial ancestor. The mitochondrial DNA sequence data from COII and ND4-5 regions therefore do not support this multiregional hypothesis for the emergence of modern humans.
Animals↗
Continuing education: who pays?
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Education, Nursing, Continuing↗