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Friday, November 21, 2008

Goodbye GATTACA, again ... do I have to change my phone number or what ... ?

GATTACA, I keep telling you it's all over between us, we are not just our "genes." It's not even clear any more that there is a gene, in that sense.

But you are just so not listening ...

If you want to predict how tall your children might one day be, a good bet would be to look in the mirror, and at your mate. Studies going back almost a century have estimated that height is 80–90% heritable. So if 29 centimetres separate the tallest 5% of a population from the shortest, then genetics would account for as many as 27 of them1.

This year, three groups of researchers2,3,4 scoured the genomes of huge populations (the largest study4 looked at more than 30,000 people) for genetic variants associated with the height differences. More than 40 turned up.

But there was a problem: the variants had tiny effects. Altogether, they accounted for little more than 5% of height's heritability — just 6 centimetres by the calculations above. Even though these genome-wide association studies (GWAS) turned up dozens of variants, they did "very little of the prediction that you would do just by asking people how tall their parents are", says Joel Hirschhorn at the Broad Institute in Cambridge, Massachusetts, who led one of the studies3.

[ ... ]

There could be scarier and more intractable reasons for unaccounted-for heritability that are not even being discussed. "It's a possibility that there's something we just don't fundamentally understand," Kruglyak says. "That it's so different from what we're thinking about that we're not thinking about it yet."

Still the mystery continues to draw its sleuths, for Kruglyak as for many other basic-research scientists. "You have this clear, tangible phenomenon in which children resemble their parents," he says. "Despite what students get told in elementary-school science, we just don't know how that works." (Personal genomes: The case of the missing heritability by Brendan Maher, Nature News (Published online 5 November 2008 Nature 456, 18-21 (2008) doi:10.1038/456018a)
See also:

Farewell, fat gene ... goodbye gay gene ... so long, sloppiness gene. And can someone please text Lamarck and tell him ...

Goodbye GATTACA: Environment and lifestyle affect which genes are actually expressed

Find out why there is an intelligent design controversy:


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