This past week I was skimming the NY Times Health section to see if any new, exciting study had been blown out of proportion to better suit the media. Funnily enough, I came across this article titled “Tug of War Pits Genes of Parents in the Fetus.” I found this the day after reading Sapolsky’s chapter about the differences between men and women. In this article it went into more detail about the findings that men and women’s genes are battling it out in the fetus. It was interesting to read that scientists were able to manipulate embryos in mice so that the offspring would either have two X chromosomes or two Y chromosomes. Those with the two X’s had a significantly larger brain but smaller bodies whereas the mice with the two Y chromosomes had a larger body but a much smaller brain. This finding got me thinking…I wondered if all the great thinkers, of both past and present, if in utero, their mother’s genes were slightly more dominant? Would that have given them such an intellectual advantage? And then what happens with the opposite occurrence? Do those individuals with significantly larger bodies have slightly smaller brains? Did their father’s genes have a slight edge over their mother’s in utero?
The article went on to Dr. Dulac’s study with imprinted genes. In her study, she was able to identify around 1,300 imprinted genes in mice. On top of finding more than the expected number of imprinted genes, she found maternal and paternal genes are activated in the brain at different times in the individual. She also found sex differences of imprinted genes on different regions of the brain. Lastly, they found an unexpected symmetry in the brain. It is expected that in each cell either the mother’s or the father’s genes would be turned off. However, in women, in the neurons in the cortex there is a much greater chance that the paternal genes will be turned off. I am still fascinated as well as humored by the idea that both your mother and your father are “telling” you what to do before you are even born.
Here’s the link to the article: http://www.nytimes.com/2010/09/14/health/14gene.html?pagewanted=2&ref=biology_and_biochemistry