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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 William Gaatjes on 1/20/2010 6:49:20 AM , Rating: 2
You're an idiot and an ass. You dive off topic and create new ones.

I can not help that you are not willing to use your brain.
You absolutely do not have any arguments.
I do notice a pattern...

I cannot take you seriously any longer. Because you must be typing your text as a yoke. It must be a yoke, or the alternative is much worse for you, because then you are a yoke. A bad one :). I will finish this response so you can have your laugh and i can have mine :) :).

By the way: I'm aethiest, so I know your type.

You must have a split personality C.W. :)

would continue to debate with you, but you already proved all I was saying: You are a science zealot, weighing the equation with no "facts" whatsoever. I left the open opportunity with stem cell research as a fluke, to see how dumb you were. The answer? NO ONE. That's right, no one has been punished or thrown out of the church for their beliefs in science. And like an OAF, you jumped right at it.

You do not debate. You call names and use non existing arguments because you do not want to read.
With respect to stem cell research, i already admitted that i do not much about that matter. I know that it is important as i have written. Again , Fail...

Nice. Clearly you are a genius. Now that I know you're a fool, there's no need to debate. Do your research kiddo, do your research. And whether or not the man who CREATED the big bang theory HAD BEEN quoted as saying the universe was 6,000 years old, trying to find a balance with religion, does not matter. He was searching for the answer, and found the answer that your punk ass scientists could not, and that you would not have.

Having a rough day at work ? :)
Did you not find something special ? :)
Open your mind a little... It would make a change.

Without beliefs, whether religious or otherwise, no one has drive. You accuse religion as an abnormally imbalanced drive .

In many posts on other dates and subjects of dailytech i have stated that man always need hope. Some people have it natural, others need some help...

I accuse people with behaviour like you. Because again you do not read. And again you just give a response without thinking first.

Well guess the @%@^$ what?? It's a balance. All of it. And religion doesn't tip the scale. There's just as much flaw to science observation. Believing one can take three aspects of controlled observation and draw a conclusion which is absolute is childish. No physics majors agree with how hardcore you are, so I'm assuming that you are not a physics major. Good job.

I think you lost it...


I instead assume you were the rebel aethiest in school, you almost definitely live in California given the brain dead calculations leaning on a left scale as well. A Virginian usually has both sides, you have one, so it has to be a well educated liberal state. California is the best bet. I know my kind.

Amazing, you are so predictable. I did not respond on purpose to make you think that i was from the USA or even on the continent Amerika. Nor am i from California or Virginia. What am i to you now :) :) :)

Make me laugh a little more ,you yoke of your parents.

"This is from the It's a science website." -- Rush Limbaugh

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