Saturday, January 29, 2011

Knockout gene study in mice prompts speculations on human behaviour #3348

Lab mice by Aaron Logan, Lightsource
In "Ma's gene does different things to pa's copy" Jessica Hamzelou (26 January 2011) reports for New Scientist on a knockout study of mice where researchers knocked out a gene called Grb10 in females and mated them with normal males.

(From the report: "Most of our genes are expressed in pairs – one copy inherited from each parent. But pairs of so-called imprinted genes have just one copy "switched on".)
What happened? The gene was expressed "only in the brain and spinal cord."* How did this influence behaviour?
Mice lacking the paternal gene groomed their mates so much that the latter lost their whiskers and fur.
So far so good. The gene helps regulate mouse behaviour. Now wait for the klunk:
Humans have the same gene, so there is a possibility that it might be influencing our own social behaviours, he adds.
"Possibility",  "might" Their caution is well advised, but the question is, why bother? Humans differ from mice precisely in that we adjust our behaviour to real or perceived circumstances, and that difference greatly reduces the importance of any similarities.

If a human mother brushed her kid's hair until it fell out, she would soon be in a supervised parenting program (at least where I live).

A study author comments,
"The most interesting human parallel is Silver-Russell syndrome," says Gudrun Moore, a geneticist at University College London's Institute of Child Health. Ten per cent of people with this growth disorder have two copies of a maternal chromosome and no copies from the father. "These individuals have not been tested for overtly dominant behaviour, though they do have speech delay, learning difficulties and lower IQ," Moore says.
Ah, just the combination of traits needed by a dominant human: speech delay, learning difficulties and lower IQ ...

A real possibility, of course, is that an enterprising researcher will do a study of such persons, find "dominant behaviour" (acting out frustrations aggressively in this case), and we will soon be nearing about a new "violence gene". Book deal to follow? (Journal reference: Nature, DOI: 10.1038/nature09651)

(*A different experimental population with the sexes reversed showed that the gene expressed itself everywhere but the brain.)

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