November 16, 2009

Time-independent evolutionary mtDNA mutation rates in Penguins

The study is reminiscent of another recent paper on Penguins, and strikes another blow against the idea that over long time periods genetic diversity accumulates at a slow rate.

Trends in Genetics, Volume 25, Issue 11, doi:10.1016/j.tig.2009.09.005

High mitogenomic evolutionary rates and time dependency

Sankar Subramanian et al.

Using entire modern and ancient mitochondrial genomes of Adélie penguins (Pygoscelis adeliae) that are up to 44000 years old, we show that the rates of evolution of the mitochondrial genome are two to six times greater than those estimated from phylogenetic comparisons. Although the rate of evolution at constrained sites, including nonsynonymous positions and RNAs, varies more than twofold with time (between shallow and deep nodes), the rate of evolution at synonymous sites remains the same. The time-independent neutral evolutionary rates reported here would be useful for the study of recent evolutionary events.

Link

10 comments:

Maju said...

I feel that there is a misunderstanding somewhere. "Greater" seems to mean slower, at least attending to the press release:

Penguins that died 44,000 years ago in Antarctica have provided extraordinary frozen DNA samples that challenge the accuracy of traditional genetic aging measurements, and suggest those approaches have been routinely underestimating the age of many specimens by 200 to 600 percent.

In other words, a biological specimen determined by traditional DNA testing to be 100,000 years old may actually be 200,000 to 600,000 years old, researchers suggest in a new report in Trends in Genetics, a professional journal
.

Ponto said...

Don't say that, mate. You'll get Dienekes ranting about the Germline theory of Mr Z, the goose with the has a disgustingly long surname.

You know what I mean, his belief that the ages of haplogroups are overestimated and should be divided by three. Of course it only applies to the so called Semitic haplogroup J1, the over estimation of the age of R1b to make it Paleolithic, and Cro Magnoid is set in Ice Age stone and cannot be similarly revised, or even recalculated.

We have much better methods in this century, than we had in the last century to estimate the ages of haplogroups.

Maju said...

Dienekes is consistent, AFAIK. He has defended that R1b in Europe is of Neolithic origin too.

In fact with the ultra-fast rates he and a few others have proposed, only Y-DNA I could be claimed (and not too safely) to be Paleolithic in Europe.

But, anyhow, the question is to get the matter clarified and stop the speculation as much as possible. Using fossil DNA is surely the only way to explain anything. Same as happened with the Neanderthal-Sapiens interbreeding controversy.

Jean said...

Write-up in Science: Penguin DNA May Reset the Molecular Clock

Scientists use the “molecular clock”—an estimated rate of DNA mutation—to date key events such as migrations and the divergence of species. But just how accurately the clock keeps time has long been debated. A new study of living and ancient Antarctic penguins, like those on Ross Island at left, suggests that DNA mutates six times faster than predicted. That could mean that some species—such as chimps and humans—could have split off from each other much more recently in time than previously thought. The finding should help improve the dating of relatively recent events, including when people domesticated various crops and animals, and when major human migrations occurred.

Dienekes said...

Dienekes is consistent, AFAIK. He has defended that R1b in Europe is of Neolithic origin too.

No, I have said that R1b has a Neolithic TMRCA but I did not say that R1b arrived in Europe during the Neolithic.

Maju said...

Sounds like a riddle: if R1b is of Neolithic age and if R1b has a West Asian center of gravity and highest diversity area but it did not arrive to Europe in Neolithic... then it is?

Let me guess: from Bronze Age Greece? *disbelief*

Dienekes said...

if R1b is of Neolithic age and if R1b has a West Asian center of gravity and highest diversity area

I see no evidence that R1b is significantly more diverse in West Asia than in Southeast Europe

http://dienekes.blogspot.com/2008/12/age-of-italian-r1b-y-chromosomes.html

Vincent said...

I see no evidence that R1b is significantly more diverse in West Asia than in Southeast Europe.

You could find such evidence in the various FTDNA geographic projects which contain R1b1b2 haplotypes. Looking only at the M269+ samples, you'd see that the "West Asian" projects (R-Arabia, Turkey, Assyrian, Armenian) have a ten marker variance (xDYS385) of 3.28: higher than the Greek project (2.44) or the Italy Project (2.68).

In fact none of the West Asian projects have a R1b1b2 variance lower than either Greek or Italy.

Dienekes said...

FTDNA projects (including the Greek DNA project) do not contain random samples of populations. From published studies I see no evidence that R-M269 is more diverse in West Asia than in SE Europe.

Vincent said...

FTDNA projects (including the Greek DNA project) do not contain random samples of populations. From published studies I see no evidence that R-M269 is more diverse in West Asia than in SE Europe.

You won't see evidence you don't want to see. And I'm not surprised at the rush to keep the truth from getting in the way of a good story.

However, if your argument is that the European projects at FTDNA are under-sampling diversity relative to the Asian ones, I think you'll have an uphill battle demonstrating it.