Wednesday, May 28, 2008

What's the Difference Between Female DNA and Male DNA?

 
Answer: The "female" DNA sequence is incomplete because it lack DNA from the Y chromosome.

A recent press release from the Leiden University (Netherlands) proclaims Leiden scientists sequence first female DNA.

This is a well-deserved winner of Jonathan Eisen's second Genomics by Press Release Award [Genomics By Press Release Award #2: Lieden University and the First "Female" Genome]. Read the award persentation speech on his blog The Tree of Life.

Congratulations to Leiden University1 for showing us how science should not be done and how science journalism is taking over from peer review publication.2.


1. "Leiden University is the oldest university in the Netherlands. It was founded in February 1575, as a gift from William of Orange to the citizens of Leiden who had withstood a long siege by the Spaniards."

2. We look forward to more press releases when the data is actually published in the peer reviewed literature.

13 comments :

  1. Thanks. This is the first reasonable comment I read on that issue and I actually was thought the same when I came across the press release. But do you think this is only hyped by LU's PR department. Sometimes I get the impression that molecular biologists, especially younger ones, are not too familiar with Mendelian genetics.

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  2. To sparc, I'm willing to bet they're perfectly familiar, and are full well aware. This whole thing smells like a shameless stunt, from top to bottom. Right down to the name of the person they picked. And frankly, this annoys the heck out of me.

    First female genome indeed! Blah.

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  3. Yes, but isn't it possible that given different selection pressures on human males and females, the autosomal genes of males and females will be found to differ in important respects? Given the very important differences in female and male development and physiology, aren't autosomal differences likely to be very important too? How will we know unless we sample a large number of males and a large numbers of females? And if, as Leiden reports, this is the first time the DNA of a human female has been fully sequenced (whereas half a dozen or so males have been sequenced), isn't that a legitimate thing to do scientifically, regardless of the way in which the completion of the sequencing is announced? Doesn't if reflect a inappropriate (sex-linked) bias to sample only the DNA sequences of males?

    Perhaps the Leiden investigators are motivated by the sense that they are pointing out a rather glaring gap in the research so far or just by curiosity about the genetics of half the human species. Of course it is not strange that males should prefer to sequence male DNA; it is a perfectly self-absorbed thing to do; but isn't science as an institution supposed to operate to remove these inappropriate biases?

    So, good for Leiden for striking a blow for real science (male egos notwithstanding) and reminding scientists to be scientific!

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  4. Its actually not possible that the sequence of autosomal genes will differ between males and females. The gene expression differs dramatically. but the sequence, no.

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  5. The sequence of genes (their order and place on the autosomes) may be identical in male and female humans. (How do we know that?) Nevertheless, alleles of particular genes will differ. I assume that the first step towards identifying and analyzing these differences (and determining whether they are indeed "male" and "female" differences or simply differences between individuals) is sequencing.

    It seems unwise to found all your conclusions about the human genome on samples from just one sex, just as it would be unwise to draw your conclusions about anatomy and physiology and variation in any species from just one sex of that species. And if anatomy and physiology (and development and behaviour) differ significantly then so (you would think) to genes.

    The Leiden news release is clearly meant to provoke, in the way that Weismann's cutting the tails off mice was meant to provoke more than a century ago. there are many other examples. That's one of the way science makes progress.

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  6. In a word, Anonymous #1? No.

    This isn't some chauvinistic plot to oppress females and to insert gender into science where it ought not be. Honest-to-god, the only thing that differs between males and females, sequence-wise, are in the sex chromosomes. The autosomal chromosomes have no way of 'knowing' which sex chromosome will end up in the gamete with it, and to the best of my knowledge, can't so-brazenly segregate that non-randomly without it showing up as a massive departure from Mendelian expectations at many other loci.

    And, given that, it's generally a good idea to have a hint that an hitherto-now unforeseen mechanism exists before you spend as phenomenally large amount of money as it costs to sequence an individual.

    In any event, your reason wasn't their stated reason. And thank god for that, because no one could take them seriously ever again if they'd done it for your reason. Not that it in any way excuses this brazen publicity stunt.

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  7. I thought male DNA was blue and female pink...
    Anyway Larry, surely female DNA already has DNA from the Y chromosomal - in the pseudoautosomal region. Any more than that and it would stray into Klinefelter's territory.

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  8. Yes, but isn't it possible that given different selection pressures on human males and females, the autosomal genes of males and females will be found to differ in important respects?

    and

    The sequence of genes (their order and place on the autosomes) may be identical in male and female humans. (How do we know that?) Nevertheless, alleles of particular genes will differ. I assume that the first step towards identifying and analyzing these differences (and determining whether they are indeed "male" and "female" differences or simply differences between individuals) is sequencing.

    Well, now I know why some people choose to post anonymously.

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  9. As to the incomplete comment:

    I think there are about 51% of people that would consider the Y chromosome as that "junk" DNA you are talking so much about...

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  10. What's the Difference Between Female DNA and Male DNA?

    Answer: The "female" DNA sequence is incomplete because it lack DNA from the Y chromosome.


    I'm not sure that I understand your answer. Are you saying that removing one single, special fragment from male DNA will result in the remaining genetic material being female DNA?

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  11. The reason that I asked for clarification is that I have a related question. Theoretically, given a modern man and a cloning process, would it be easier to modify the DNA of a female chimpanzee to create a modern woman or would it be easier to modify the DNA of a man to create a perfect female? How many steps are required for each of these processes?

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  12. The Genises account is that God "Created" male and female and their sequence . They are equally marvelous and important in the differnces tje DNA males in their body, soul and Spirit and thier purpose in life.

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  13. Before this 'Unusual' discovery I think the females were thought to be more complete genetically becasues they have a pair of X chromosome and males incomplete as they have only one of X and Y. In my opinion the old scintific wisdom looks still more promising.
    Anu.

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