Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Health

A resolution to the molecular clock debates?

Gene ExpressionBy Razib KhanOctober 30, 2006 9:05 PM

Newsletter

Sign up for our email newsletter for the latest science news

Heterogeneous Genomic Molecular Clocks in Primates:

The rate at which mutations accumulate in a genome, referred as a "molecular clock," is an instrumental tool in molecular evolution and phylogenetics. Different types of mutations occur via distinctive molecular pathways. In particular, while most mutations occur from errors in DNA replication, spontaneous deamination of methylated CpG dinucleotides is another important source of mutation in mammalian genomes. Molecular clock studies typically combined all types of mutations together. In this paper, the authors analyze molecular clocks of replication-origin and methylation-origin mutations separately. By utilizing high-quality sequence data from several primate species and fossil calibration, the authors demonstrate that the two types of mutations follow statistically different molecular clocks. Methylation-origin mutations accumulate relatively constantly over time, while replication-origin mutations scale with generation-times. Therefore, the genomic molecular clock, as a whole, is shaped by the molecular origins of mutations that have accumulated over time. The authors' results have direct implications on phylogenetic analyses, estimation of species divergence dates, and studies of the mechanisms and processes of evolution, where molecular clocks are imperative.

I really don't have much to add, their own summary covers all the bases. Molecular clocks are critical in reconstructing phylogenies, and in human evolution their utility is so great that they have arguably revolutionized paleoanthropology. Obviously the great "rate debate" within phylogenetics matters here, as a million years here and there is essential in framing and generating hypotheses about the environment in which our hominid ancestors evolved and speciated.

    3 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In