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Published on: November 11, 2016
Variation in the molecular clock of primates
Priya Moorjani1, Carlos Eduardo G Amorim2, Peter F Arndt3
1Department of Biological Sciences, Columbia University, New York, NY 10027; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142; pm2730@columbia.edu mp3284@columbia.edu.
Primate evolution rates vary significantly. CpG transitions offer a more reliable molecular clock for dating divergence events, like human-chimp and human-gorilla splits, due to their consistent mutation patterns.
Area of Science:
- Evolutionary Biology
- Genomics
- Molecular Evolution
Background:
- Primate evolution dating often assumes constant substitution rates, but this is questionable.
- Mammalian substitution rates vary due to life history traits, suggesting similar variation in primates.
Purpose of the Study:
- To investigate variation in substitution rates across primate lineages.
- To identify reliable molecular markers for accurate primate divergence dating.
Main Methods:
- Whole-genome analysis of 10 primate species (OWMs, NWMs, apes).
- Focus on neutral autosomal sites, controlling for gene conversion and CpG methylation.
- Analysis of different mutation types, particularly CpG transitions.
Main Results:
- Substitution rates varied up to 64% between NWM and ape lineages.
- Rates were slightly higher in chimpanzees (2%) and gorillas (7%) compared to humans.
- CpG transitions showed more consistent rates, behaving like a molecular clock.
Conclusions:
- Primate substitution rates and mutational spectra are not constant.
- CpG transitions are the most reliable markers for dating primate evolutionary events.
- New estimates for human-chimp (12.1 MYA) and human-gorilla (15.1 MYA) divergence were provided.
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