Tug of War Pits Genes of Parents in the Fetus

[groovedaddy]

Under Mendel’s laws of inheritance, you could thank mom and dad equally for all the outstanding qualities you inherited.

But there’s long been some fine print suggesting that a mother’s and father’s genes do not play exactly equal roles. Research published last month now suggests the asymmetry could be far more substantial than supposed. The asymmetry, based on a genetic mechanism called imprinting, could account for some of the differences between male and female brains and for differences in a mother’s and father’s contributions to social behavior.

A person gets one set of genes from each parent. Apart from the sex chromosomes, the two sets are equivalent, and in principle it should not matter if a gene comes from mother or father. The first sign that this is not always true came from experiments in which mouse embryos were engineered to carry two male genomes, or two female genomes. The double male and double female mice all died in the womb. Nature evidently requires one genome from each parent.

Biologists then made the embryos viable by mixing in some normal cells. The surprising outcome was that mice with two male genomes had large bodies and small brains. With the double female genome mice, it was the other way around. Evidently the maternal and paternal genomes have opposite effects on the size of the brain.

http://www.nytimes.com/2010/09/14/health/14gene.html?th&emc=th

[BridgeTheGap]

1. I always wondered why I so often felt pulled in two different directions. n.t

[ejpoeta]

2. so men have brawn women have brains?? lol

[laconicsax]

3. I read a book on imprinting a while ago:

http://www.amazon.com/Imprinted-Brain-Balance-Between-Psychosis/dp/1849050236/ref=sr_1_1?ie=UTF8&s=books&qid=1284498019&sr=8-1">The Imprinted Brain: How Genes Set the Balance of the Mind Between Autism and Psychosis

It's an interesting read that proposes autism and psychosis as opposite ends of a spectrum that's the result of the tug-of-war between maternal and paternal genes. If mom's genes win, you're born smaller and are likelier to move towards schizophrenia and psychosis. If dad's genes win, you're born bigger and are likelier to move towards autism.

ETA: The article mentions the birth size disparity, but differs from the above book in that the article says that smaller birth size is for the sake of future children, whereas the book says it's for the sake of the mother's health (smaller fetuses are less resource-intensive) and her welfare during birth (big babies are harder to push out than small ones).

[Odin2005]

4. I have that book, good read.