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While the mammalian Y chromosome (males only) may be much smaller than the X chromosome that predominates in females (males have one X, females two), this males only chromosome is evolving much faster. As a result male primates were found to be evolving faster than females.  (Source:
The Y chromosome is evolving fast to deal with genetic pressures of varying mating habits, such as chimp group mating

Modern biochemistry and genetics is just beginning to unlock the complex secrets of evolution, the process in which organisms change over long periods of time through random genetic variation and selective pressures.  With a handful of genomes sequenced, scientists can now start mining this data to find interesting trends and evidence of the course evolution is taking, particularly in humans.

A provocative and intriguing new study reveals that past thought on the Y chromosome, the chromosome that instructs mammals to develop into males, may be entirely flawed and that the chromosome, previously thought to evolving at a crawl, may in fact be evolving far faster than other chromosomes.  Human females typically have two X chromosomes, while males have an X and a Y chromosome.

It was previously thought that autosomes (non-sex chromosomes) and the X sex chromosome featured greater diversity (faster evolution) than the Y sex chromosome, a smaller chromosome.  According to the new study, led by Jennifer Hughes, a postdoctoral researcher in Whitehead Institute Director David Page’s lab.  The research indicates that primate males may be evolving significantly faster than females.

To determine how fast the Y chromosome was changing, the scientists needed a point to compare our Y chromosomes against.  The human Y chromosome had been comprehensively sequenced by the Page lab and the Genome Center at Washington University in 2003.  A promising target was DNA from chimpanzees -- a close relative of humans on the evolutionary tree.  However, the 2005 sequencing of the chimpanzee genome excluded the Y chromosome, mostly, due to its hundreds of repeating sequences that threw off sequencing techniques at the time.

Undeterred, researchers at the Page lab and Genome Center at Washington University completed sequencing the chimpanzee Y chromosome, using newer techniques.  What was discovered was amazing.  The Y chromosome, thought to be a musty unchanging stretch of genes had changed significantly between humans and apes in terms of structure and content.  Approximately one third to a half of genes found in the human version of the chromosome were lost in the chimp chromosome, since chimps diverged from humans in the evolutionary tree.

Professor David Page compares these changes to a constantly renovated home, stating, "People are living in the house, but there’s always some room that’s being demolished and reconstructed.  And this is not the norm for the genome as a whole."

Wes Warren, Assistant Director of the Washington University Genome Center, another top genetics expert, agrees that the findings are extraordinary, "This work clearly shows that the Y is pretty ingenious at using different tools than the rest of the genome to maintain diversity of genes.  These findings demonstrate that our knowledge of the Y chromosome is still advancing."

One thing that may be driving faster evolution of the male sex chromosome is differing mating habits between species.  Where as humans typically take a single partner during sexual intercourse, numerous chimpanzees often mate with a single female in a short time period.  Males who produce more sperm, or whose sperm is better at impregnating females will have a better chance at beating the other males' sperm and passing on his genes.

To give an idea of just how profound this effect is, the difference between the rest of the human and chimp chromosomes is only 2 percent.  That means that the male sex chromosome is evolving nearly 15 times faster, or more, on average than the female genome.

The Page lab and the Washington University Genome Center are now looking at the Y chromosomes of several other mammals to further determine if this faster rate of male evolution is a characteristic of primates only, or other mammal lines as well. 

The study on the work was published in the prestigious journal Nature, and can be found here.

The research was funded by National Institutes of Health (NIH) and the Howard Hughes Medical Institute (HHMI).

Where as chimps have evolved to cope with the genetic pressures of group sex, human males and females have evolved on a different course.  Recent research indicated that human females are slowly evolving to be shorter and to carry more weight.

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By Belard on 1/15/2010 2:52:47 PM , Rating: 2
when you do not know of which religion the person is, is quite frankly stupid.

Its easy to figure out from his "Jesus" thingy that he's not: Islamic, Jewish, Buddhist, Shinto or Catholic. So no, it would be stupid to not be able to figure that out.

answers to your crappy attack of christianity.

I'm not attacking Christianity. Just stupidity and organized religion.

A: Ever hear "There is no God but God?" Just as meaningful, eh?

B: So, Gos has split personality disorder? My Son is not me, I am not my son. Jesus was not God, for God is only God. Filling two entities into the same title is stupid, er never mind, (bush & cheney were both president - duh)

C: So? It goes back to the stupidity of combining two people into one.

D: I wasn't being specific to the poster. I was explaining the stupidity of a religious marketing campaign that effectively puts their God below man. And BEFORE you go back to the God is he/Jesus blah, that campaign is supposed to be aimed at people who don't know/think they know the Bible.

E: But many Christians hate Jews. Thing is, the Christian Bible has been re-written over and over again (the new 2010 version!), while Judaism is still the same.

F: Or if God created everything; he created homosexuals, blacks, Islam, the air, malaria, fleas (explain why Noah saved the 2 Fleas), cancer, baldness, incest and more. If Adam & Eve were the first two humans, who did their children have sex with to reproduce? ewwwwwwwwwwww!
But in the end, your God has an ego problem in that if YOU choose to not follow the bible to the letter (you can't, due to interpretations and contradictory rules, ideas and stories) - you're damned. So wheres the love?

You're concept of hell also does not match everyones either.

Huh? Did I describe hell? I was going by the interpretations of the religions.

t's either accept this God's payment for your sins or be full of sin in the presense of god when he returns

So a child molester who rapes his own children and goes to Church twice a week is forgiven by God, but an Indian in South America whose never meet a white man goes to Hell? Sounds perverted to me.

Remember, white men from Europe thought the Earth was flat and that their ships would fall of the Edge of the world. Too stupid to understand the stars and the moon. Yet men from thousands to years before understood a lot more, even calculated the size of the Earth roughly. It was religion that taught those men that the Earth why flat. hmmmmmm.

Stick to science when you argue against religion.

Stick to Religion as it doesn't belong in Science, the Government or our schools.

The universe is full of more galaxies than there are humans. Never mind the 100~200 billion stars in our galaxy alone.

"We are going to continue to work with them to make sure they understand the reality of the Internet.  A lot of these people don't have Ph.Ds, and they don't have a degree in computer science." -- RIM co-CEO Michael Lazaridis

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