molecular clock


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molecular clock

n.
1. An assumed approximately constant rate of change over evolutionary time in the nucleotide sequences of DNA molecules and the amino acid sequences of protein molecules.
2. A technique based on this assumption, in which the amount of time since two species or other taxa diverged from a common ancestor is estimated by measuring the number of differences between certain gene or protein sequences of the taxa.
References in periodicals archive ?
We estimated the time of most recent common ancestor for all gene segments by using a relaxed molecular clock (Table).
As a molecular clock it has a potential to define the time of divergence between closely related species and finally depict the molecular distance among the species.
The very large discrepancy led to the creation of more realistic molecular clock methods, called "relaxed" clock methods, and almost 50 years later, they predicted the oldest animals to have lived about 850 million years ago.
The host supervisor has recently discovered that brown adipose tissue (BAT) metabolism is not only controlled by classic thermogenic regulation, but also by the circadian rhythm of the bodys molecular clock.
Slot and his colleagues created a molecular clock, using bacterial samples collected over time and evolutionary analysis to trace the history of copper resistance.
For the first time, we have shown that simply adjusting the time when food is made available alters the molecular clock in the hippocampus and can alter the cognitive performance of mice.
Understanding the molecular clock at play, regardless of the presence or absence of an embryo during the window of implantation, could help to identify biomarkers of endometrial receptivity.
Through a tool known as the Molecular Clock, our scientists can tell how old a marker is and, by looking at where it is most common in the world, can also say where it originated.
Worobey and his colleagues developed an unprecedentedly accurate molecular clock approach and used it to reconstruct the origins of the 1918 pandemic H1N1 influenza A virus (IAV), the classical swine H1N1 influenza virus and the post-pandemic seasonal H1N1 lineage that circulated from 1918 until 1957.
The researchers then used a select set of transcription factors to turn back the molecular clock just a little on these committed myeloid cells, turning them into blood progenitors that readily engrafted and differentiated when transplanted into mice.
The GTR model as determined previously to best fit the substitution model was used to estimate the phylogenetic trees under the assumption of strict or relaxed (uncorrelated lognormal) molecular clock.
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