Saturday, April 25, 2009

Essence of Male - i

What is a male being?

Is male essentially a Heterosexual? No.
Is male essentially a Homosexual? No.
Is male essentially a Bisexual? No.

Male is Asexual.

What makes a male? Y-chromosome.
What is a Y-chromosome? An asexual chromosome.

The essence of male is the essence of its Y-chromosome.

Battle of the Sexes - i

Another change in neo-X that Bachtrog suspects is taking place is the elimination of genes that are harmful to females. Biologists have realized recently that some genes have opposite effects in males and females, and evolution is a tug of war between males jettisoning genes that they find detrimental only to have females put them back, and vice versa.

"A good place to put sexually antagonistic genes that are beneficial to one sex but detrimental to the other is on the sex chromosomes," she said. The Y always ends up in the male, she said, so genes on the Y chromosome won't affect females.
"Conversely, the X chromosome becomes feminized with genes that are good for the female but detrimental to the male," said Bachtrog, adding that the X also becomes demasculinized, losing genes that are of use only in the male.

Via Science Daily.

Thursday, April 16, 2009

Origins of Indians: Version 11.0

Indian skull shape:
Anthropometry has been traditionally used in the reconstruction of history of particular region. This is one of its numerous pseudo-scientific applications. We know that;
- Communities of a particular lineage/s in a region can change its skull shape because of change in lifestyle (nomadic to sedentary). eg. China and Middle East
- Tribal populations because of restricted food supply and region can drift towards certain type of skull shape.
- Of course, looks of matrilineage generally prevails upon in mixed population as it's more stable. This is in the sense men move or change in any region.

However, anthropometry has been widely used to stereotype the looks of a particular region. Then employ this stereotypical look to give an identity based on present day identities to faceless old populations of that region. And there are still many people who think this is more scientific than skin colour studies to identify the groups.

But thanks to Population Genetics now we can get clear picture of old populations and their relationship to one another. Here too just like skin colour based notions, skull shape based ideas fail miserably.

In India, it's been traditionally thought that Mundas predate Dravidians and IE speakers. Many a time their skull shape has been considered as a standard. Now we know that just like their language their main male lineage (Haplogroup O2a) is observed in Austro-Asiatic populations of SE Asia/S China. But their matrilineage is typical to India. Their looks can't be considered as a standard. We now know that their male ancestry skull shape was entirely different. Therefore, present day look of Mundas is misleading.

Other examples:
We can find such examples in other parts of the world too.
Generally, Finnish were considered as epitome of Nordic look(Blond/Dolichocephalic). But now we know that a big chunk of male ancestry(Y-haplogroup N1c) could have had entirely different look. Only their matrilineage is completly European. Therefore, present day look of Finnish is misleading.

North Africa:
In the case of Mundas and Finnish the original male look would have resembled present day East Asian look. A similar story could be found in North Africa. Light skinned North Africans are predominantly Y-haplogroup E1b1b. This haplogroup and it's closest branch Y-haplogroup E1b1a could be found among their southern dark skinned population. But their matrilineage is predominantly European. Therefore, the present day look of North Africans is misleading. Hilariously, there are Europeans who claim ancient Egyptian civilization as their own. Those people are handicapped by American model of white skin distribution thro' European males. But European male lineages are insignificant in comparison to their female lineage either in North Africa or West Asia. Considering how patriarchy prevailed in the past, probably, dark skinned Africans have higher claim on Egyptian civlization than Europeans.

Wednesday, April 01, 2009

A Father is Complete Parent; Mother is Half - i

We have seen that ignorant wise men of the past had made complete fools of themselves by thinking semen is seed. But the modern science is giving some respect to their one idea that man is complete but woman is not. It is in parenting we find the difference. As of now, it's the only area we find the clear differences between the sexes.

A discussion on what one mean by clear difference would be relevant here. There are studies that talk about various differences between the sexes. But in those studies difference is expressed in terms of average difference of statistical distributions of certain measurements. Frankly, I don't understand how to interpret them. I wonder when I see these results, do my opinion about them also gets normally distributed? Or do I need to select a certain interval and view it as true and the rest false? But the practical application of statistical analysis is not only to measure the variability but also to minimize it by tweaking the variables. Hence, it can be also viewed as a measure of success or failure of our optimization.

Considering all these complications, I would prefer having binary opinion. This of course requires;
- binary results for any experimentation
- no room for optimization

And I have found in the case of parenting this could be obtained. I have already blogged about couple of studies on this:
1. Mother's positive influence on daughter. Mother' no influence on son. Father's influence on both son and daughter.
2. Mother's negative influence on daughter.

There is a new study that further supports the second point.

the participants listened to 30-second audio recordings of remarks from their mother. Some comments were praising, some were critical and others were neutral in content. The comments were previously recorded over the telephone with the permission of the mothers. The participants were also asked to rate their mood on a scale from one to five after hearing the different kinds of remarks.
Despite being healthy and reporting similar conscious reactions to the recorded comments, the formerly depressed showed different activity in their brains, compared to those who had never been depressed. "When we asked them how they felt after being criticized, they responded in the same way as the controls did," said Hooley. "But when we looked at the brain scans, the patterns of activation were quite different. So this is happening under the radar of awareness."

The results of those studies are captured in the following tables.

Father's Influencepositivenegative

Mother's Influencepositivenegative

Thus we can say that father is a complete parent as he can influence both his son and daughter but mother is just half as she can influence only her daughter.

Now what about the combined influence of parents? Especially when one is positive and the other negative. There would be influence nevertheless but will it be positive or negative? It is very clear that there can't be any combined influence on son. What about the daughter? I haven't come across any studies on them. I can't apply logical AND or OR function here. We have to understand here, positive or negative they just complete the influence and hence true. To understand the combined influence we need to understand the underlying biological basis for this.

The first clue could be found in mother's non-influence on her son. The only reason why a mother can't influence her son could be the difference in sex chromosomes or SRY region of Y-chromosome in particular. Therefore, everything boils down to sex chromosomes. And this in turn gives further clue why a father can influence both his son and daughter. Now our interest is what happens when one of the parents have positive and the other negative influence. A simple model is mother influences thro' her X-chromosome and father thro' his. It's all Epigenetics (Epi=Beyond; Genetics).

We know that a defective gene expression is suppressed by a corresponding normal gene. This we can view as negative getting nullified by positive. Taking this concept further we can say that negative epigenetic behaviour is suppressed by positive epigenetic behaviour. Hence, a daughter can have positive outlook even with just one parent being positive about her.