A common inversion under selection in Europeans

[Nadvojvoda Janez Kranjski]

A refined physical map of chromosome 17q21.31 uncovered a 900-kb inversion polymorphism. Chromosomes with the inverted segment in different orientations represent two distinct lineages, H1 and H2, that have diverged for as much as 3 million years and show no evidence of having recombined. The H2 lineage is rare in Africans, almost absent in East Asians but found at a frequency of 20% in Europeans, in whom the haplotype structure is indicative of a history of positive selection. Here we show that the H2 lineage is undergoing positive selection in the Icelandic population, such that carrier females have more children and have higher recombination rates than noncarriers.

More info HERE

[Vitor]

more neanderthal genes!


Yes europeans are different!

more info here:
http://www.nytimes.com/2005/01/17/s...680f0812a639acd

It promotes longevity and fertility!

Dr. Stefansson said that another property of the inversion, though one not described in today's article, is that it is associated with longevity. DeCode scientists have located two sites on Icelanders' genomes where there is some genetic variant that promotes longer lifespan. The chromosome 17 inversion, it turns out, lies at one of these sites. It occurs at much higher frequency in women over 95 and in men over 90 than in the normal population. "It seems to confer on people the ability to live to extreme old age," Dr. Stefansson said.

[Vitor]

There is still hope without contraceptives we have more fertility!

[Vitor]

this map now makes more sense...

[Nadvojvoda Janez Kranjski]

Last update: January 16, 2005 at 9:14 PM

DNA region has a European influence

Nicholas Wade, New York Times

January 17, 2005


Researchers in Iceland have discovered a region in the human genome that, among Europeans, appears to promote fertility and maybe longevity as well.

Though the region, a stretch of DNA on the 17th chromosome, occurs in people of all countries, it is much more common in Europeans, as if its effect is set off by something in the European environment. A further unusual property is that the genetic region has a much more ancient lineage than most human genes, and the researchers suggest, as one possible explanation, that it could have entered the human genome through interbreeding with one of the archaic human lineages that developed in parallel with that of modern humans.

The genetic region was discovered by scientists at DeCode Genetics, a biotechnology company in Reykjavik, Iceland, which has made the Icelandic population, with its comprehensive genealogy and medical records, a prime hunting ground for the genetic roots of common diseases. Their finding is published in today's issue of Nature Genetics.

The report seems likely to receive considerable attention, even though it raises as many questions as it answers. "I thought it was one of the most interesting papers in population genetics I have ever read," said Nick Patterson, a mathematician at the Broad Institute in Cambridge, Mass., who advised DeCode on the article but has no other connection with the company.

The DNA region came to light during the search for a schizophrenia-causing gene, which turned out not to be there. But the DeCode researchers noticed that the DNA sequences they had examined did not seem to agree with those in the standard human genome sequence, said Kari Stefansson, DeCode's chief executive.

The lack of agreement turned out to be caused by the fact that the region exists in two forms in the Icelandic population. The region is not a single gene but a vast section of DNA, some 900,000 units in length, situated in the 17th of the 23 pairs of human chromosomes. In some Icelanders, the DeCode team found, the section runs in the standard direction, but in others it is flipped. Looking for any physical consequence, the DeCode researchers found that women carrying the inverted section tended to have slightly more children.

The section carries several known genes, not one of which has any obvious connection with fertility. But the inversion does increase the rate of recombination, the shuffling of genes between generations that is a major source of genetic novelty. That could account for some of the increase in fertility.

The DeCode scientists found that the chromosome-17 inversion is present in 20 percent of Europeans, the same frequency as in Iceland. The inversion seems to have been favored by natural selection among Europeans in fairly recent times, perhaps the past 10,000 years. "Maybe something switched it on in the European environment, such as an interaction with diet," said David Reich, a population geneticist at the Broad Institute.

http://www.startribune.com/stories/484/5189895.html

[Arawn]

So it wasn't just the fish after all. What about Japan, thats another country famed for its long life expectancies.

[Vitor]

Ainu neanderthal!

[Nadvojvoda Janez Kranjski]

Scientists Find Effect of Natural Selection on Human Genome

Jan. 16 (Bloomberg) -- Scientists in Iceland have uncovered a genetic variation whose female carriers tend to have more children, a discovery that shows Charles Darwin's concept of natural selection at work in modern humans.

Women with the variation have a statistically significantly higher number of children, according to the study, which is based on genetic data from more than 29,000 Icelanders. The study will appear in the Jan. 23 edition of the journal Nature Genetics.

The variant carriers' genes also tend to more easily combine with their mates' genes, which produces more genetically diverse offspring, according to the study. That correlation suggests that there is a survival advantage to being able to produce diverse offspring, said Kari Stefansson, chief executive of DeCode Genetics Inc. and a lead author on the study.

``Even though we as a society have been struggling with it, evolution values diversity,'' Stefansson said in an interview.

The discovery also raises questions about the history of human evolution, Stefansson said. The variation, which the scientists think was introduced into the gene pool about 50,000 years ago, is found in 20 percent of Europeans but is rare in Africans and almost entirely absent in East Asians, according to the study.

The fact that the variation is almost exclusive to Europeans raises the possibility that modern humans migrating out of Africa crossbred with an earlier species of hominids they encountered along the way, according to the study.

Reykjavik, Iceland-based DeCode developed models during the study that will help it evaluate other genetic variants that may be linked to human diseases or defects and develop treatments for them, Stefansson said.

http://www.bloomberg.com/apps/news?p...cHoYo&refer=us

[Vitor]

This is the most non political correct genetic work I ever saw!
(and the most IMPORTANT one)

Are they saying that european evolve more rapidly?

[Gil]

Genes may indeed help to increase life expectancy but they alone do not. An healthy life and all that is inherent to that (good diet, access to medicine, disease prevention measures, clean environment and hygiene) in the end dictate whether you life longer or not. Even if you are genetically predisposed to live longer than the "normal" human if you live in an unhealthy environment you will live much less.

[Awar]

Also, how can a country like Russia be included in this?
First of all, it's only 50-something % ethnic Russian,
other, it's famous for people dying young due to alcohol.

I'm sorry, but it makes no sense to me.

If we had such maps from ALL the periods of human existence,
then we could make sense out of it.

For example, I doubt that medieval Europe had a longer life expectancy
than medieval Middle-East.

[Vitor]

The one that put the world map was I...
Awar they tested it in the same population.

That is 20% of the iceland population lived longer and have the gene than the others 80%...

I am the one extrapolating to the world!

[Awar]

Umm, I'm not speaking against you, I just think it's obvious
that countries which are richer live longer. Look at the emirates.
I bet they had a shorter life expectancy 100 years ago. Much shorter.

[Nadvojvoda Janez Kranjski]

"Researchers in Iceland have discovered a region in the human genome that, among Europeans, appears to promote fertility and maybe longevity as well."

[Vitor]

Originally Posted by Awar

Umm, I'm not speaking against you, I just think it's obvious
that countries which are richer live longer. Look at the emirates.
I bet they had a shorter life expectancy 100 years ago. Much shorter.

80% of europeans don't have the gene, it's only 20% of the europeans that have the gene, so this 20% only marginally improve the average European longevity.

I guess I should not put that map, it doesn't prove anything!

What about that theory of their's that europeans with those genes were able to produce more diverse offsprings?
I guess this is the same as saying:
"some Europeans evolve more rapidly"!

[Nadvojvoda Janez Kranjski]

Gene Arrangement Makes Some Europeans More Fertile
Sun Jan 16, 2005 07:31 PM ET


WASHINGTON (Reuters) - Researchers working in Iceland said on Sunday they identified a genetic pattern that makes some Europeans more fertile. The genetic pattern, known as an inversion, is a stretch of the DNA code that runs backwards in people who carry it.

Usually, such rearrangements of a chromosome are harmful to carriers. But this one causes carriers to have more children each generation -- giving them what is known as a selective advantage, the researchers reported.

The finding, published in Monday's issue of the journal Nature Genetics, opens some interesting questions about human evolution, the team at Iceland's DeCODE Genetics said.

"We found that almost 20 percent of people in Iceland have at least one copy of this inversion," DeCODE spokesman Edward Farmer said in a statement.

"We then turned to other databases to see whether it existed elsewhere and how common it was. It turns out to be fairly common in European populations but quite rare in Africa and virtually absent in Asia."

More than 29.000 Icelanders donated DNA samples to a database open to scientists, which DeCODE specializes in studying.

Genes are carried on structures known as the chromosomes. The DNA code varies from person to person, but the genes and other part of the code generally lie along the same chromosomes in the same order.

This large stretch of DNA is on chromosome 17, Augustine Kong and Kari Stefansson of DeCODE found. They are checking to see whether the inversion affects the function of the genes contained in it.

About 21 percent of all Europeans they looked at have the same inversion, which they named H2, but just 6 percent of Africans and 1 percent of Asians.

The effects of the H2 inversion are not seen on an individual level, as each carrier produces an average 0.06 more children. But across populations and generations, it adds up, the researchers said.

Calculations suggest the inversion has existed for about three million years, the researchers said.

"This predates the emergence of anatomically modern Homo sapiens in Africa (150,000 years ago) and may even predate the origin of the genus Homo (2.5 million years ago)," they wrote. It could be that the inversion has survived in the human genetic code for that long.

Or it could be that modern Homo sapiens bred with earlier species, such as Homo erectus, and inherited the genetic variation that way. The two species may have lived side by side for a time before Homo erectus went extinct, sometime between 400,000 years ago and 50,000 years ago.

And the researchers say the inversion makes carriers more fertile. In each generation, an H2 carrier has about 3.2 percent more children than people without the sequence.

That is enough of an advantage to have "profound consequences" on evolution, Nature Genetics said.

http://www.reuters.com/newsArticle.j...toryID=7338451

[Nadvojvoda Janez Kranjski]

Originally Posted by Awar

Umm, I'm not speaking against you, I just think it's obvious
that countries which are richer live longer. Look at the emirates.
I bet they had a shorter life expectancy 100 years ago. Much shorter.

The results were given for one population (individuals within one population).

[Vitor]

Originally Posted by Janez

The results were given for one population (individuals within one population).

Yes, but that was only for the fertility/longevity association with that gene

Because they tested several other population for that dna code, maybe they had only fertility/longevity data for Iceland.

The DeCode scientists found that the chromosome 17 inversion is rare in Africans, almost absent in Asians, but present in 20 percent of Europeans, the same frequency as in Iceland. The inversion seems to have been favored by natural selection among Europeans in fairly recent times, perhaps the last 10,000 years. "Maybe something switched it on in the European environment, such as an interaction with diet," said Dr. David Reich, a population geneticist at the Broad Institute.
http://www.nytimes.com/2005/01/17/s...680f0812a639acd

Several world population were tested!