molecular clock


Also found in: Medical, Wikipedia.

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 will develop innovative methods of super-resolution microscopy and of quantification of protein turnover using a fluorescent molecular clock.
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.
Comparisons of different molecular clock models and tree priors were performed similarly to a method of Bakker et al.
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 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.
At the cellular level, circadian rhythms originate from self-sustained, autoregulated, cyclic expressions of clock genes, which constitute the molecular clock.
Daily or circadian rhythms include the sleep-wake cycle, and rhythms in hormone release are controlled by a molecular clock that is present in every cell of the human body.
The discord between the two for the animal phyla may be as much as 500 million years," and concluded, "the idea that there is a universal molecular clock ticking away has long since been discredited" (15).
In addition, AhR signaling affects molecular clock genes to influence glucose metabolism.
Leader of the study, Dr Nathalie Nagalingum, Research Scientist at Sydney's Royal Botanic Garden said a molecular clock has revealed today's species are totally different from those growing in the Jurassic period which began 200 million years ago.
2006) are "inconsistent" and how this affects the results of molecular clock dating analyses and inferred diversification patterns.
Full browser ?