| Great Y and stupid Feminists. |
 |  |  |
| Y "Jerome Burne" Guardian 2 The female equivalent of the Y - genetic information passed only from mother to daughter - is known as mDNA. This is the DNA of the mitochondria, the powerhouse of every cell. For a few years there has been broad agreement that the mitochondrial Eve lived around 143,000 years ago, which seems to make nonsense of the 59,000 years ago that Nature Genetics reported for the "Y-Adam". In fact, it's not as daft as it seems. What the research shows is that the different chromosomes now found in the human genome were not selected for all at once. Around 143,000 years ago, a variation of mDNA emerged from the pre-human gene pool and proved to be, in computing terms, a "killer application", driving all the others out of business. Like any successful mutation, it popped up in more and more bodies, until all the other versions died out. That's why women today all have variants on the new, improved "Eve" mDNA. The same thing happened with men and the Y, only it took another 84,000 years for the evolution of the super-successful version that eventually wiped the floor with its rivals. Exactly what it did isn't clear, but it was probably something to do with fertility. "Something happened to the record between 50,000 and 60,000 years ago," says Peter Oefner, a biologist at the Stanford DNA Sequencing and Technology Centre in California, and an author of the study in Nature Genetics. "We started at ground zero again." Buried in the paper, and virtually unnoticed by all commentators, is a political time bomb involving the Native Americans. Everyone has seen those pictures of fur-clad mammoth hunters arriving in the virgin territory of North America at the end of the last ice age. The notion that they were the first has always been an important part of Native American mythology, but evidence has been growing that the continent was well-populated long before their arrival. In the past few years, a dozen or so ancient skulls have been unearthed in North America, and not only do they date from a time before the arrival of the mammoth hunters but their shape and proportions have little in common with those of northern Asians. Instead, they look like people from south-east Asia and the Pacific. The issue is politically very sensitive and there have been bitter disputes between Native American groups and various archaeological teams, but genetics is now confirming the story of the skulls. Two years ago, Douglas Wallace of the Centre for Molecular Medicine at Emory University School of Medicine, based in Atlanta, Georgia, tackled the Native American issue head-on. Working with mDNA, he reported discovering a set of variations known as "haplogroup X" whose implications were dynamite. This X factor is found among Native Americans and among Europeans but not - and this is the important bit - in Siberian groups. Attempts to find it among south-east Asians failed. The implication of the Nature Genetics paper is that the smoking gun has turned up. Possibly because of the political tensions involved, you have to look hard to find it, but buried at the end of the article is the following: "Native Americans are located between Eurasians and East Asians, indicating common ancestry with both." In other words, they are descended not only from people of the Pacific but from a group that also travelled east and became the founders of European stock. The arrival of Columbus could be seen as just the final stage in a circumnavigation of the globe that had begun 20,000 years earlier. In a paper published earlier this year, Dr Spencer Wells of the Wellcome Trust Centre for Human Genetics, based in Oxford, who was involved in this research, suggests what might have been going on. "One of the very old Y markers we are studying, known as M45, originally came from southern central Asia around 40,000 years ago," he says. "It looks as if these people are the common ancestor of both the western Europeans and the Native Americans." But the new tools that are bringing the Y into sharper focus don't just tell us about the movements of ancient people - they can also tell you, if you are a man, how much of your genetic code you share with other men of the same name. "We have found that a person's genotype and their surname are incredibly closely linked," says Professor Bryan Sykes of the Institute of Molecular Medicine in Oxford. The link comes from the fact that men inherit both their name and their Y chromosome from their father. In a preliminary study, investigating the genetic make-up of men called Sykes, the professor found that 50% had the same Y chromosome. That means that for 700 years, since surnames began in England, the Sykes lineage has been largely unbroken. Further research has shown the same proportion for other names, too. One implication is that infidelity, leading to children calling the wrong man Daddy, is not as common as other surveys have suggested. Previous estimates put the figure at between 5% and 10%, while the work on Sykes suggests it is nearer 1%. Another implication is that it may soon be possible to make a guess at the name of a criminal from the traces of DNA he leaves at the scene of the crime. Internet policy analyst Andy Carvin saw for himself the possibilities this throws up when his attempts to trace his family tree went cold in Busk in Ukraine. He approached American-based website Family Tree DNA (www.familytreedna.com) for help, and after he had mailed them a sample of DNA, swabbed from the inside of his cheek, he got two surprises. First, from his Y markers, they ascertained that he was one of the priestly Cohens; second, they had the name of a man whose markers suggested he and Carvin had a common ancestor within the past 250 years. Carvin went to meet him. "We hit it off immediately," he says. "I felt that I was visiting one of my uncles." Over smoked whitefish and bagels, they looked through family photos. "His dad looked like mine and his son looked like me when I was younger. Only he was a hell of a lot better looking." But if the new findings on the Y look like bringing together men who were previously strangers, they also confirm that the battle of the sexes is rooted in our genes. The idea that men and women have different agendas is now fairly familiar. While men can theoretically father an almost infinite number of children, women are strictly limited in the number they can have, so it makes sense for men to be more promiscuous and women more choosy. What is not so widely appreciated is that the breakaway by the Y allowed for the development for two rival enclaves where genes that benefited one sex or the other could take refuge. A gene that finds a home on the Y chromosome doesn't have to worry about the effect it has on females, because it is only going to find itself in male bodies. Perhaps the most devilish example of this comes from fruit flies. The male's sperm contains a poison that damages the sperm of any other male it encounters, giving it an edge in knocking out rival suitors. An unfortunate side effect for the female is that this sperm is also toxic to her, which means that the more often she copulates, the shorter her life span. It doesn't seem that human sperm can directly affect women in this way, but there is evidence that males go in for sperm competition. Among primates, this is most famously practised by chimpanzees who are prodigious sperm producers because when females regularly have sex with a number of males, the one who can most effectively pump up has a greater chance of fertilising the egg. Last year, Dr Chung-I Wu and his colleagues at the University of Chicago reported finding that the genes involved in making sperm protein, in both humans and gorillas, were mutating very fast. "This suggests that they are under intense competitive pressure," he says. The Y contains the largest concentration of sperm-producing genes and researchers are now looking to see which ones are involved in this competition. Having a Y chromosome may put male children at risk from the mother's immune system while in the womb. Last year, Ray Blanchard, professor of psychiatry at the University of Toronto, made a surprising discovery. He found that younger brothers, but not sisters, are more likely to be slightly asymmetrical than their older siblings, and the more older brothers you have, the more asymmetrical you are likely to be. As if that wasn't strange enough, other research had already shown that the same is true of homosexuality: the more older brothers you have, the more likely you are to be gay. What is going on here? Blanchard believes that something in a womb that has already held a male responds increasingly strongly to the next one. As females are untouched, he thinks the Y chromosome is probably involved. Now, there is a gene on the Y chromosome that produces a masculinising protein called AMH (anti-Mullerian hormone) which stops the development of the glands that would otherwise turn into womb and ovaries. But AMH can also trigger the mother's immune system, and the antibodies she produces can interfere with AMH's other job of switching on the genes that are involved in masculinising the brain. So the reason for the birth order effect could be that the mother's immune responses get stronger the more often they are triggered. Y's unilateral declaration of independence not only placed it in permanent conflict with X, but also transformed it into an island. It is this isolation that is the other distinctive feature of the Y. Gradually, it became the wild frontier of the genome, where the normal housekeeping rules did not apply. However carefully it is done, copying always creates errors in the end, whether it's monks with manuscripts or DNA. When egg and sperm cells are being produced, the pairs of chromosomes can swap genes back and forth, weeding out ones that have been damaged. But the breakaway Y had closed its borders, creating badlands where there is no updating or repairing of genes. So, like abandoned settlements, the structures gradually decay and once-functioning genes turn into useless shells as the irresistible entropy of copying errors gradually accumulates. |
Feminist was the Revenge, of some men, against women. NOW: Go Clean My Office. |
"For every miner who 'oppressed' his wife at home, there was another social power (men and WOMEN), an employer or manager, who oppressed 100 miners in the pits. And the idea that women were the only oppressed 'victims' in all of this is ridiculous, and completely beyond belief." |
"The idea that women, particularly western women, have not had power throughout recent History is, of course, a feminist-inspired falsehood, and it was created mostly by emotionally-deficient women to provide further fuel for their personal campaigns of hatred against men." |
|
|
Nature 463, 536-539 (28 January 2010)
Published on line 13 January 2010
Men more evolved?
Y chromosome study stirs debate Women may think of men as primitive,
but new research indicates that the Y chromosome - the thing that makes a man male -
is evolving far faster than the rest of the human genetic code.
A new study comparing the Y chromosomes from humans and chimpanzees, our nearest
living relatives, show that they are about 30 percent different. That is far greater than
the 2 percent difference between the rest of the human genetic code and that of the
chimp's, according to a study appearing on line, Wednesday in the journal Nature.
These changes occurred in the last 6 million years or so, relatively recently when it
comes to evolution.The Y chromosome appears to be the most rapidly evolving of
the human chromosomes,” said study co-author Dr. David Page, director of the
prestigious Whitehead Institute in Cambridge and a professor of biology at MIT.
It's an almost ongoing churning of gene reconstruction. It's like a house that's constantly
being rebuilt.
Before men get too impressed with themselves, lead author Jennifer Hughes offers
some words of caution: Just because the Y chromosome, which determines gender,
is evolving at a speedy rate it doesn't necessarily mean men themselves are more
evolved.
Researchers took the most detailed examination of the Y chromosome, which females
do not have,
of both humans and chimps and found entire sections dramatically different.
There were even entire genes on the human Y chromosome that weren't on the chimp,
said Hughes, also of the Whitehead Institute.
The two-year research took twice as long as expected because of the evolutionary
changes found, Hughes said.
There is a bit of a proviso to the comparison to other chromosomes. While all human
and chimp chromosomes have been mapped, only two chimp chromosomes have been
examined in great detail: Y and chromosome 21. Yet, there's still enough known to make
the claim that the Y is the speediest evolver, Hughes and Page said.
Until recently the Y chromosome was considered the Rodney Dangerfield of genetics,
especially because it had fewer genes than other chromosomes. A few years ago some
researchers even suggested that the Y chromosome was shrinking so that in 50,000
years
it would just disappear and so would men.
The story is not as cut and dried as many would have liked to predict," Hughes
said.
It's kind of fun to say that men are going to die out, but the science is proving - now that
we've got data - that that's not true at all.”
-AP
Published on line 13 January 2010
Men more evolved?
Y chromosome study stirs debate Women may think of men as primitive,
but new research indicates that the Y chromosome - the thing that makes a man male -
is evolving far faster than the rest of the human genetic code.
A new study comparing the Y chromosomes from humans and chimpanzees, our nearest
living relatives, show that they are about 30 percent different. That is far greater than
the 2 percent difference between the rest of the human genetic code and that of the
chimp's, according to a study appearing on line, Wednesday in the journal Nature.
These changes occurred in the last 6 million years or so, relatively recently when it
comes to evolution.The Y chromosome appears to be the most rapidly evolving of
the human chromosomes,” said study co-author Dr. David Page, director of the
prestigious Whitehead Institute in Cambridge and a professor of biology at MIT.
It's an almost ongoing churning of gene reconstruction. It's like a house that's constantly
being rebuilt.
Before men get too impressed with themselves, lead author Jennifer Hughes offers
some words of caution: Just because the Y chromosome, which determines gender,
is evolving at a speedy rate it doesn't necessarily mean men themselves are more
evolved.
Researchers took the most detailed examination of the Y chromosome, which females
do not have,
of both humans and chimps and found entire sections dramatically different.
There were even entire genes on the human Y chromosome that weren't on the chimp,
said Hughes, also of the Whitehead Institute.
The two-year research took twice as long as expected because of the evolutionary
changes found, Hughes said.
There is a bit of a proviso to the comparison to other chromosomes. While all human
and chimp chromosomes have been mapped, only two chimp chromosomes have been
examined in great detail: Y and chromosome 21. Yet, there's still enough known to make
the claim that the Y is the speediest evolver, Hughes and Page said.
Until recently the Y chromosome was considered the Rodney Dangerfield of genetics,
especially because it had fewer genes than other chromosomes. A few years ago some
researchers even suggested that the Y chromosome was shrinking so that in 50,000
years
it would just disappear and so would men.
The story is not as cut and dried as many would have liked to predict," Hughes
said.
It's kind of fun to say that men are going to die out, but the science is proving - now that
we've got data - that that's not true at all.”
-AP
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|
|