I know I’ve been writing a lot lately about the differences between men and women, and perhaps some readers are a bit fed up with the topic. Well, too bad, because today’s NYT reports new science shedding light on this often cloudy subject, and it’s looking more and more as if biology is the culprit.
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.
Beginning way before the body produces a penis on a child destined to be male, the embryonic future dude may already be cherry-picking traits that have more to do with the end product that we have known.
In another novel pattern, she found sex differences in imprinted genes in different region of the brain, particularly those concerned with feeding and with mating behavior.
Sex differences in the brain are usually attributed to the influence of hormones, but sex-based differences in imprinting may be another mechanism by which nature spins male and female brains out of the same genome.
The research is, as it should be, heavy going with a lot of sciency stuff about imprinting … a sort of tuning out some genes while letting others do the driving.
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.
Hinting that there’s a difference between man and mouse, researchers are guessing that because of monogamy, fewer genes are imprinted … in humans … so less asymmetry?
Working in mice, the Harvard team showed that around 1,300 genes are imprinted. Dr. Dulac said that she expects a substantial, though lesser, proportion to be imprinted in people — maybe some 1 percent of the genome — because humans are more monogamous than mice and so the parents’ interests are more closely aligned.
Really?
Can it be true that millions of years of developing our big brains and thousands of years of socialization getting us all civilized and stuff have made such a difference?
Much of the available evidence comes from mice, and people may to some extent have emancipated themselves from imprinting when they evolved the pair bond system of mating about a million years ago. But the pair bond does not mean perfect monogamy, and in its deviations from perfection there is plenty of room for imprinting to thrive.
No shit.
A collection of my short stories:
I'm in this one, too ...
And I'm in here, as well ...
Paradise Preoccupied 
that have the ability to choose rather or not to conceive but mostly prevalent with conceiving fraternal twins as well.
If any one can remember biology classes in high school surely can remember that any dominating attributes in living plants like roses for an example; a red rose cross-cut into a white rose would grow a pink rose (Mendel’s Law). The dominant attribute would be the red color rose. How about facial features, hair texture and skin color, all would come from the most dominating gene from both biological parents and why not some behaviors, likes and dislikes as well. Take human twins, separate them away from each other and they most likely will still have the same behaviors with very little difference concerning their likes and dislikes. Unfortunately most siblings aren’t able to physiologically know for sure if they are related or not. When I was living in England there was a story on the BBC News channel and the web http://news.bbc.co.uk/2/hi/uk_news/7182817.stm and in the local newspaper where I lived with my husband. It was about a couple that got married where they found out after they decided they wanted children their blood test was biologically matched the same. They were twins, brother and sister. Everyone wanted to know how did this happen. Both the man and woman were separated at birth and some how they found each other and were very sexually attracted to each other and consciously formed a romantic relationship not knowing they were biologically connected to each other at the same time. They were reciprocal of each other as they consciously made their decision that they were physically attracted to each other but at the same time biologically unreciprocal to procreate. I believe that as we learn about certain human biological behaviors that we will consciously be more aware of these human chromosomes that are linked to these behaviors and these behaviors will be looked upon as important physical indicators allowing us to recognize certain chromosomal aberrations that are already understood as important contributors to our own evolution. When Mendel explains that the dominate gene will hide the recessive gene, I’m not totally convinced. Maybe for most are convinced but for me I don’t think so. Because when my children were growing up especially my son I had noticed that he grew in spurts. Like one week his body would be proportionally uneven. Or some times he would look very much like me and then a few weeks later he would look more like his father. So how much dose a dominant sex gene suppress a recessive sex gene in a male with the same recessive sex gene in a female given from the same parents? Is the race between the dominant gene and the recessive gene more physically obvious in a male than in a female when it seems these genes appear to be racing for the finish line? And are females and males both at the same time evolving towards growing slower during childhood so that their brains will grow even bigger and smarter? One more last thing, I think it’s the common denominator that can create an almost perfect monogamy. I think the common denominator should have a lot to do with what a couple sees as most important similar healthy characteristics that they have in each other and at what level they are in during their courtship and imprinting would have to be not so similar to one another.
Thanks for your comment, Betsy …
Wow. That is not a comment, it is a book. A very well thought out one. Thanks for the info Sandra and Betsy. It’s very interesting. Science is always evolving, but it seems like the more they discover about the human genome, the more questions arise that they can only guess at. Human behavior is a fascinating subject for me, one that I’ve been studying for many years. But on a basic level, it seems to me (and I could be predjudice) that women are evolving faster than men. Men are still beating their chests and allowing testosterone to be a major motive in the decisions they make. Most men run on instinct in that area (the more women the merrier) without questioning the wisdom of their actions. Women lust, that’s for sure, and we make many mistakes in our choice of men. But to me, the majority of women look for more in a man than just what’s on the surface. We want to be loved as we love. Deeply, completely, and monogamously. Men? There are a lot of good ones out there that share the same needs and beliefs, but it looks to me like they are terribly outnumbered. Am I stll bitter over the fundamental differences between men and women? I guess so. Evolution…it’s a long haul.