Sentences with phrase «molecular clock»

Sometimes referred to as tip dating, tip calibration is a method of molecular clock calibration in which fossils.

A master clock in the brain communicates that control to molecular clocks in peripheral tissues.

To figure out when land plants and fungi originated, the team analyzed 119 such molecular clock genes common to living species of animals, plants and fungi.

Different studies often report substantial discrepancies between age estimates for groups of organisms implied by the fossil record and estimates generated by molecular clocks.

This divergence between the two forms of malaria was used by the scientists as a kind of molecular clock.

A relaxed molecular clock analysis including Ptilocercus suggests that treeshrews arose approximately 63 million years ago.

Relaxed molecular clocks for dating historical plant dispersal events.

«Lethiscus also has broad impacts on evolutionary biology and people doing molecular clock reproductions of modern animals,» says Anderson.

Consequently, attempts to date evolutionary branchings with molecular clocks have resulted in widely different estimates among researchers.

Evolutionary biologists use so - called molecular clocks to determine when species branched off from family trees.

Molecular clock approaches allow us to estimate when two closely related modern species split from a common ancestor by comparing their DNA.

Molecular clocks use the rate at which DNA sequences change to estimate how long ago new species arose, assuming a relatively steady rate of genetic evolution.

Molecular clock assumption by allowing the ability.

But if the K - Pg extinction caused avian molecular clocks to temporarily speed up, Berv and Field say this could explain at least some of the mismatch.

Mutations that accumulate in DNA are like molecular clocks.

Molecular clocks allow scientists to trace the ancient tree of life, even when fossil evidence is scarce, and help find the branches that led to modern humans.

If true, then running all those viral molecular clocks backward should establish when the virus that infected the children first appeared.

Through molecular clock analyses, which combine genome - scale molecular data with fossil calibrations, the team could work backwards to estimate when saprotrophic and mutualistic lineages last shared common ancestors based on the amount of divergence.

Clearly, biologists aren't ready to give molecular clocks up — the clocks may not be Swiss, but they take a licking and keep on ticking.

New fossil evidence suggests human ancestors may have split from chimps as early as 10 million years ago, bringing fossil evidence in line with data from molecular clocks

Given that the investigators have previously shown the influence of the host molecular clock on the gut microbiota, they will also ask if taking this NSAID at different times of day might lead to higher efficacy and less side effects in animal models and eventually in humans.

Yet the order in which those three other groups appeared has been a mystery and has stymied molecular clock studies.

Dr. Zohar Ben - Moshe from the Yoav Gothilf Lab identified 14 light - entrained molecular clock genes in the zebrafish system using messenger RNA sequencing and microarray analysis.

Passenger Pigeon genome research was lead by Dr. André Elias Rodrigues Soares, a computational and laboratory biologist with a history in molecular clock phylogenies.

Molecular clock analyses always come up with older dates than fossils, he notes, so «I always take these estimates with a pretty big grain of salt.»

The Pennsylvania State University research team, led by evolutionary biologist Blair Hedges, based their findings on the so - called molecular clock.

Most adult cells have little to no telomerase activity, and the progressive shortening of their telomeres serves as a kind of molecular clock that limits the cells» — and, some believe, an organism's — life span.

«The bottom line is that, by speeding up avian genetic evolution, the K - Pg mass extinction may have temporarily altered the rate of the avian molecular clock,» says Field.

This move also caused TIM levels to drop, but this time the protein did not begin to build up again because the molecular clock was advanced by the time - zone switch.

The fluctuating proteins synthesized by clock genes control additional genetic pathways that connect the molecular clock to timed changes in an animal's physiology and behavior.

Please read this lucid description of the hunt for molecular clocks that Scientific American brought to you the better part of two decades before the three researchers confront jet lag on their trip to Stockholm.

How does the molecular clock regulate an individual's day - night activity?

Evidently the flies» molecular clocks were initially stopped by the transfer, but after a delay they resumed ticking in the pattern of the new time zone.

Once we had found two genes that functioned in concert to make a molecular clock, we began to wonder how the clock could be reset.

Perhaps one of these, or a component of the molecular clock itself, will become a favored target for drugs to relieve jet lag, the side effects of shift work, or sleep disorders and related depressive illnesses.

The molecular clock resoundingly exonerated the medics.

This is important because current DNA studies, known as «molecular clocks», which are used to estimate how long ago a group animals originated, suggests the first animals appeared before these burrows.

Using genetic changes as a molecular clock, they conclude that Papuan and Aboriginal Australian ancestors diverged perhaps 37,000 years ago, long before Australia and New Guinea were separated by rising seas.

Recently they took a big step closer by creating the first oscillator — a molecular clock — made solely of DNA.

Instead of using one model with one set of assumptions and constraints, the researchers analyzed the data with every molecular clock model available.

Previous genetic analyses of frog evolution focused on mitochondrial DNA and how long the molecular clock had been ticking for mitochrondrial genes.

But recent «molecular clock» research suggests the link between speciation and environmental change is weak at best.

Using those genetic data as a molecular clock, they proved that the HIV outbreak began long before the accused medics even started working at the hospital.

The molecular clock approach is based on the principle that mutations accumulate in the genomes of all organisms over the course of time.

It seemed to be sensitive enough to measure the exact amount of decay that occurs on an hourly basis — and that amounts to a molecular clock for dating proteinaceous materials like silk.

By calibrating what scientists call the molecular clock — the hypothesis that mutation occurs at a predictable rate — to the panda separation 12 million years ago, one group of researchers suggests the polar bear's appearance as a species is a relatively recent phenomenon.

The circadian clock is a molecular clock that is probably found in every body cell.