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Human Males Evolve At a Faster Pace Than Females 454

Posted by CmdrTaco
from the can't-say-i'm-surprised dept.
Tisha_AH writes "A report by the Whitehead Institute indicates that the human Y chromosome present in males is evolving at a furious pace. Across the chromosome there can be as much as a 33% difference within humans alone. The portions of the chromosome evolving fastest are related to sperm production."
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Human Males Evolve At a Faster Pace Than Females

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  • by metamechanical (545566) on Thursday January 14, 2010 @10:29AM (#30763700)
    From the very first paragraph of the article:

    Contrary to a widely held scientific theory that the mammalian Y chromosome is slowly decaying or stagnating, new evidence suggests that in fact the Y is actually evolving quite rapidly through continuous, wholesale renovation.

  • by Tony (765) on Thursday January 14, 2010 @10:37AM (#30763802) Journal

    Right, but the gene distribution present within the population is indicative of the changes in genotype within the population.

    The notion of evolving males is not silly. That's why peacocks have big bright displays, while peahens are boring brown. (This is even within the wild population of peacocks.)

    This is called "sex selection," and Darwin wrote extensively about it.

  • by ByOhTek (1181381) on Thursday January 14, 2010 @10:37AM (#30763808) Journal

    A population doesn't need to be independent, just distinct.

    As TFS said, there is rapid evolution on the Y chromosome in the human race. With the exception of a few anomalies, this means males.

    Yes the female population benefits from this, but these accelerated mutations and shifts in allele frequency are not within the female population, therefor they are not within the group that is evolving at a more rapid pace.

  • Re:The cynical... (Score:4, Informative)

    by Slur (61510) on Thursday January 14, 2010 @10:48AM (#30763956) Homepage Journal

    It could simply be taken as a form of compliment - specifically, by way of self-deprecation. It's not uncommon, nor considered problematic in many cultures. (As one who has not yet subscribed to any particular culture, I have no opinion as to whether it offends me or not.)

  • Old News... (Score:5, Informative)

    by kyriosdelis (1100427) on Thursday January 14, 2010 @10:50AM (#30763988)
    This has been known for a long time. It is called "male driven evolution". This happens because in humans (and most animals) the cells producing sperms divide about 6 times more than the egg cells. And guess what: studies in a human gene that has a homologue in both X and Y chromosomes, showed that (you guessed it) the Y homologue changes about 6 times faster than the X one.
    Did I say old news? 1947 old:
    “The primordial oocytes are mostly if not all formed at birth, whereas spermatogonia go on dividing throughout the sexual life of a male. So if mutation is due to faulty copying of genes at a nuclear division, we might expect it to be commoner in males than females.”
    “ we should expect higher mutability in the male to be a general property of human and perhaps other vertebrate genes.”
    J. B. S. Haldane. 1947. The mutation rate of the gene for haemophilia and its segregation ratios in males and females. Ann. Eugen. 13:262-271.
  • by Sciros (986030) on Thursday January 14, 2010 @11:13AM (#30764332) Journal

    If the Y contained nothing, then males would inherit exactly zero traits from their fathers.

    That bit is wrong... fathers provide 23 chromosomes in total, just like mothers. Daughters inherit plenty of traits from their fathers, after all, and they don't have a Y chromosome.

  • Re:At last... (Score:3, Informative)

    by afidel (530433) on Thursday January 14, 2010 @11:17AM (#30764410)
    But it DOES have an affect on the speed which is why there are slightly more males born than females.
  • Re:At last... (Score:3, Informative)

    by realityimpaired (1668397) on Thursday January 14, 2010 @11:22AM (#30764512)

    Does she believe that all embryos start as female, and then some (approx half) evolve to male? By that statement, I had to *FIGHT* to be a male.

    Actually, all embryos do start as female. Maybe not genetically, but they develop as a female fetus, and then later in pregnancy the ovaries drop to become testicles and the penis develops. Hormonal and chemical differences in the mother's uterus can prevent this from happening properly (leading to people with a female body who are genetically male), or can lead to androgen insensitivity syndrome (having a male body that's completely unresponsive to testosterone and other androgens and will not enter puberty naturally) or any other number of intersex conditions....

    male/female, when speaking outside of the genetic context, is a pretty wide spectrum, actually, and is definitely not binary. Even when speaking in the genetic context, it's not always as cut and dry as being either XX or XY.

  • by Dishevel (1105119) * on Thursday January 14, 2010 @11:29AM (#30764674)
    Maybe not. The article clearly states though that in this case the Y chromosome is evolving faster. That chromosome is only present in males. So. Males of the human species are evolving faster than the females at this time. These are very simple facts. Only made muddy and complicated by the fact that saying so sounds politically incorrect and as such can not be left alone as fact and must be downplayed.

    God I hate this kind of shit

  • by cream wobbly (1102689) on Thursday January 14, 2010 @11:34AM (#30764758)

    Males are not an independent population, that's correct. It's also a strawman, because they don't have to be. Females are subject to the same mutations, but obviously, they don't express. From TFS: "the human Y chromosome present in males is evolving at a furious pace".

    The rest of what you say is true also. And has nothing at all to do with the subject at hand.

  • by Vegeta99 (219501) <rjlynnNO@SPAMgmail.com> on Thursday January 14, 2010 @11:35AM (#30764772)

    Hell, they get the second X from Dad, so it's his fault she's a girl anyway!

  • by hazydave (96747) on Thursday January 14, 2010 @11:56AM (#30765206)

    That "6000" number may (you didn't provide data) only be touted by 0.1% of religious groups, but they are the loudest out there... the radial, vocal far right.

    That number, and the whole Young Earth fairy tale, is a very recent invention. In the 1700s, there was no major Christan group (or any other Western Religion) espousing such nonsense. Various groups had once believed in a "young earth", but it has been soundly rejected by all of them, centuries ago. This is why most Europeans, even the devoutly religious, hear this stuff and do wonder about America.

    This all started in the early 1800s, in the USA. William Miller, a New York farmer, came to believe that the Bible contained coded information, including the date of the "end of the world". This took form as the Seventh Day Adventist movement... followers of Miller organized and prepared for his calculated end of the world. He gained a national following in the mid 1800s, and finally named a final year, based on his calculations: 1843. I'm guessing he screwed up somewhere. Then it was somewhere between March 21, 1843 and March 21, 1844. When that year passed by, he got out his pencil, did the calculations again, and pronounced the real date as April 18, 1844. After that passed, he posted a new date: October 22, 1844. Curiously, the world also didn't end then. This final one became know as "The Great Disappointment".

    Anyway, curiously enough, this crazy person's religion did not fail based on these failures, but continued to grow, backed by followers... Miller himself went into seclusion. In 1923, George McCready Price, a Millerite and Seventh-day Adventist, wrote a book called "The New Geology" (he was not, in fact, a geologist), which established the earth at somewhere between 6,000 and 10,000 years old, and claimed "The Genesis Flood" responsible for many modern geological features of the earth. This one book pretty much started the ball rolling among this fringe types.

    As for this not being a mainstream belief... true. But not as true as you think. In 2008, Gallop conducted a poll, that indicated 44% of US adults agreed with the statement "God created human beings pretty much in their present form at one time within the last 10,000 years or so".

    As for that number being thrown out... I understand this. I really don't care what various creatins believe, whether it's young earth, Santa Claus, Easter Bunny, or the Flying Spaghetti Monster... as long as they keep it to themselves. But these folks have had a very, very dangerous effect on the policies of the USA, at least during the eight years of the Bush Administration. This does not sit will with those of us, such as myself, who value science over superstition, logic over "what I feel in mah gut", etc.

  • by ByOhTek (1181381) on Thursday January 14, 2010 @11:59AM (#30765274) Journal

    You're horribly out of date, circa 2003 when I was in undergrad, there were about half a dozen geenes, including those (as mentioned in TFS) related to sperm production.

    Also, if you have a wall that you paint once a year, and a second wall that you also paint once a year, but additionally paint a small corner of the second wall weekly as well, which wall gets painted more often? The second: while most of the wall is not as often changed, that doesn't negate the fact that part of it is changed more frequently.

    Same thing: most of the DNA in a male changes at the same rate as in a female, but part of it changes faster.

    Also, mutations on non-coding DNA could turn it into coding DNA. Also note that the Y chromosome is partially haploid - this makes sense with that - males are the test subjects of the species (with allele crossover, although rare genes could hypothetically get tossed on and off the Y chromosome.)

  • by reverseengineer (580922) on Thursday January 14, 2010 @12:01PM (#30765312)
    The Y and X chromosomes are not very similar at all. Even though the Y chromosome imaged in a karyotype does admittedly resemble about half of a chromosome, structurally, it's all there. There is a long and short arm with a centromere dividing them, just like the other chromosomes. The Y chromosome really is much smaller than the X, though. There are about 2000 genes on the X chromosome, and roughly 80 on the Y chromosome. Unlike the non-sex-determining chromosomes, there is almost no recombination between the X and Y (that is to say, the genes on each are not shared between the two).
  • by fastest fascist (1086001) on Thursday January 14, 2010 @12:15PM (#30765554)

    The headline plays with the common association between "evolution" and "improvement" in order to gather angry responses and its fair share of taunting.

    No it doesn't. "To evolve" is a neutral term, quite apart from "better" and "worse". If people want to get riled up over that, it's their own damn fault.

  • Re:At last... (Score:3, Informative)

    by afidel (530433) on Thursday January 14, 2010 @12:50PM (#30766176)
    There aren't. Males occur at ~51.3% of live births, females become more common over time as they die at an older age and die less frequently in their youth.
  • by yabos (719499) on Thursday January 14, 2010 @01:18PM (#30766708)
    Male pattern baldness coming from the mother's side is a myth
    http://ca.askmen.com/sports/health_60/92_mens_health.html [askmen.com]
  • by Kingleon (1399145) on Thursday January 14, 2010 @02:04PM (#30767536)
    <quote><p>Absolutely untrue. Evolution is mutation plus culling. Without the culling, you do not have evolution.</p></quote>

    No. Without culling, you do not have selection. Selection and evolution are not the same thing.

    Evolution just means change. Mutational change, if it is passed down and inherited, is evolutionary change, even if it is entirely neutral to the fitness of the individuals. This is why people have argued for decades about the importance of genetic drift in the evolution of organisms. Some say that everything is selected for (everything effects fitness) while others argue that a great deal results from random neutral mutations which spread through genetic drift. Neutral evolution is an important aspect of molecular evolution, for example.

    What isn't evolutionary change are changes that aren't inherited, like changes that result from phenotypic plasticity.
  • by Anonymous Coward on Thursday January 14, 2010 @02:36PM (#30768186)

    Absolutely untrue. Evolution is mutation plus culling.

    As a population geneticist at a major center for research and genetics, I can tell you your definition is absolutely untrue. Google 'neutral evolution'.

    Evolution is any change in the gene pool of a species and is caused by four seperate forces: Mutation, migration, selection, and drift. Any one of these forces can cause evolution. Evolution is not synonymous with adaptive evolution. Most evolution likely occurs without the force of selection, since most mutations are neutral or nearly neutral.

  • Re:The cynical... (Score:3, Informative)

    by Chris Burke (6130) on Thursday January 14, 2010 @04:09PM (#30769816) Homepage

    And then there's all his black racist jokes. He's constantly making fun of black hip hop and R&B stars, black culture in general, and even had a lengthy bit about "niggers" which was used not in that brotherly way, but in a distinctly derogatory way. Like "Niggas love to not know! [cheerfully]'Man I don't know that shit!'" and "Niggas always blame the media. 'Oh it's the media. It's just the media.' When I'm gettin money from the ATM, I'm not looking over my shoulder for the media!"

    I think you're just remembering selectively.

  • Re:The cynical... (Score:2, Informative)

    by irm (759254) on Thursday January 14, 2010 @04:49PM (#30770442)
    Agreed. An under-used word: http://en.wikipedia.org/wiki/Misandry [wikipedia.org]
  • by Chris Burke (6130) on Thursday January 14, 2010 @05:11PM (#30770854) Homepage

    "Evolving" might not be the right term. "Changing" might be better.

    Except those are really the same thing.

    Evolution is simply changes in allele distribution in a population over time. That's all it means. It doesn't have to involve mutation, and it doesn't even have to be towards better adaptation. Natural Selection is the mechanism by which these changes can be selected for or against according to their survival benefit and is why evolution generally tends toward better adaptation, but it needn't be so to be evolution. Even if it isn't a case of sexual selection either. Evolution simply means changes.

    Any disadvantageous mutation quickly perish. Very few changes are beneficial.

    Only if they are sufficiently detrimental (though many are, and "quickly" is usually while the organism is still a tiny bundle of cells). Also many changes can be mostly neutral and thus have no effect on survival -- if the organism can survive and reproduce, the changes were "good enough", even if we humans might be tempted to call them "disadvantageous". In the long term they may affect the success of the population with those changes, but maybe not.

    If the rate of mutation increases rapidly, it is either due to intense environmental pressure, such as arriving on the Galapagos Island, or it is due to the fact that there is no environmental pressure on this genetic treat, and you survive either way. Literally Degeneration.

    But if you survive to reproduce, then the changes in your genome weren't "bad". "Good" and "bad" are only in the context of the environment in which they are being tested. So "good" changes are ones that allow you to survive in that environment. But when the environment changes, then the notion of "good" and "bad" could change entirely, and not necessarily in the way that you might have pre-supposed.

    "Degeneration" doesn't really mean anything in the context of evolution.

  • by viking80 (697716) on Thursday January 14, 2010 @07:59PM (#30773108) Journal

    Here is an example to illustrate. The facts can be discussed, but understand the point.

    Human brainsize was limited to surviving natural birth. With c-section, this is not an issue, and any brainsize is OK. Since a big brain is a very good survival tool, in not too many generations all infants will have brains too big for natural birth, and can only survive with a c-section. This is certainly evolution, but since we understand and have created this environment artificially, we should also understand what it may cause in the future.

    Gene therapy and other procedures allow a long list of fatal diseases(in the absence of modern medicine) to spread throughout the population. This is what I mean by degeneration.

    Also, in the US, it looks like there is a strong selection to be a poor immigrant from latin america.

    And a good education is certain extinction. Any graduate degree results in so few offspring and that branch of humans will be gone in a few centuries.

"Stupidity, like virtue, is its own reward" -- William E. Davidsen

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