Protein clock dating

27-Feb-2020 10:37

protein clock dating-48

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Molecular clocks For the past 40 years, evolutionary biologists have been investigating the possibility that some evolutionary changes occur in a clock-like fashion.Over the course of millions of years, mutations may build up in any given stretch of DNA at a reliable rate.It is composed of three proteins, Kai A, Kai B and Kai C, that together form a circadian clock.At the beginning of the cycle, Kai A (at the top, PDB entry These clocks have a period of about 24 hours, but as you can imagine, they are not exact.So cells have a way of synchronizing their clocks with the outside world.The clock in our brain is synchronized by exposure to light.When a stretch of DNA does indeed behave like a molecular clock, it becomes a powerful tool for estimating the dates of lineage-splitting events.For example, imagine that a length of DNA found in two species differs by four bases (as shown below) and we know that this entire length of DNA changes at a rate of approximately one base per 25 million years.

The protein is shown from side here, with two subunits removed to show the tunnel that runs through the middle.

The phosphates that tick off the hours of each day are added to a serine and a threonine on each subunit.