April 23, 2014

Nicholas Wade: Males not going extinct after all

In the New York Times, Nicholas Wade reports:
Researchers See New Importance in Y Chromosome 
By NICHOLAS WADE   APRIL 23, 2014

There is new reason to respect the diminutive male Y chromosome. 
Besides its long-known role of reversing the default state of being female, the Y chromosome includes genes required for the general operation of the genome, according to two new surveys of its evolutionary history. These genes may represent a fundamental difference in how the cells in men’s and women’s bodies read off the information in their genomes. 
When researchers were first able to analyze the genetic content of the Y chromosome, they found it had shed hundreds of genes over time, explaining why it was so much shorter than its partner, the X chromosome. All cells in a man’s body have an X and a Y chromosome; women’s have two X chromosomes.
The finding created considerable consternation. The Y had so few genes left that it seemed the loss of a few more could tip it into extinction. 
But an analysis in 2012 showed that the rhesus monkey’s Y chromosome had essentially the same number of genes as the human Y. ... 
Dr. Kaessmann calculates that the Y chromosome originated 181 million years ago, after the duck-billed platypus split off from other mammals but before the marsupials did so. 
... “Throughout human bodies, the cells of males and females are biochemically different,” Dr. Page said. The genome may be controlled slightly differently because of this variation in the 12 regulatory genes, which he thinks could contribute to the differing incidence of many diseases in men and women. 
Differences between male and female tissues are often attributed to the powerful influence of sex hormones. But now that the 12 regulatory genes are known to be active throughout the body, there is clearly an intrinsic difference in male and female cells even before the sex hormones are brought into play. 
“We are only beginning to understand the full extent of the differences in molecular biology of males and females,” Andrew Clark, a geneticist at Cornell University, wrote in a commentary in Nature on the two reports.
  

18 comments:

Anonymous said...

Besides its long-known role of reversing the default state of being female

Female is not the default state. The fetus is undifferentiated until about week 8 and can go either way.

Genes are needed to make it go one way or the other. Check SRY and WNT.

Anonymous said...

http://www.newcriterion.com/posts.cfm/Professor-Donald-Kagan-to-receive-second--Edmund-Burke-Award--7443

Overkill?

Anonymous said...

“We are only beginning to understand the full extent of the differences in molecular biology of males and females,” Andrew Clark, a geneticist at Cornell University, wrote in a commentary in Nature on the two reports."

Balderdash. We ALLLLLLLLLLLLLLL know that gender is a social construct!

Anonymous said...

With only 12 genes, gene phenotype mapping should be fairly nice and easy, at least for simple traits like body shape, height and so on.

Although these gene variations may do complex things in the presence of different hormonal environments (take the female hormonal setup and these genes wouldn't do what they do, and would result in a person different to normal males or females), we can at least get a ceteris paribus model of what they do.

Anonymous said...

I guess sex reassignment surgery is going to have to get a lot more invasive if there are biochemical differences. The masterminds behind World War T will crack that nut presently.

Anonymous said...

But an analysis in 2012 showed that the rhesus monkey’s Y chromosome had essentially the same number of genes as the human Y.

There's a guy joke in there somewhere just trying to get out. The trouble is women have no sense of humor.

sunbeam said...

I'd heard of this before, or at least think what I heard of is what he is referring to. I am referring to the idea that the Y chromosome in mammals (or only humans? Never sure about that) inevitably shortens over many generations of breeding.

It never made much sense to me, because there are lots of mammal species in the world, and new ones occasionally arise.

Yet none of the ones with vastly shorter lifespans and generations are extinct? At least as a result of this issue? Or did they become extinct from it, and we of course didn't notice.

I always wondered why someone didn't run a computer simulation using this theory.

I have a seat of the pants feeling we wouldn't have any surviving mammals, but maybe I don't understand the process or this particular theory well enough.

sunbeam said...

Okay, one more thing that shows my ignorance of biology I guess.

"Dr. Kaessmann calculates that the Y chromosome originated 181 million years ago, after the duck-billed platypus split off from other mammals but before the marsupials did so. "

So... the duck-billed platypus doesn't have a Y-Chromosome? Fish? Insects? Reptiles? Early mammals? As far as I know gender exists in all of them, and well, without a Y-Chromosome why bother with having sexes at all?

I guess I don't understand what these guys are driving at or talking about.

Anonymous said...

So, what can we do to add the "Alpha Male" gene to all the beta computer programmer and engineer types that deserve to reproduce so that Western civilization can go forward?

Clearly, the current crop of Alpha Males is doing a good job of kowtowing to the PC'ers in bringing down the West, so we need a change of leadership, right?

Anonymous said...

Genes are needed to make it go one way or the other. Check SRY and WNT.

Well, you really should check WNT4.

However, as far as female being the default state, how can this happen if that were the case:

Serkal syndrome[edit]
A disruption of WNT4 synthesis in XX humans produces Serkal syndrome. The genetic mutation is a homozygous C to T transition at cDNA position 341.[5] This causes an alanine to valine residue substitution at amino acid position 114, a location highly conserved in all organisms, including zebrafish and Drosophila. The result is loss of function, which affects mRNA stability. Ultimately it causes female to male sex reversal.[5]


From the ever truthful Wikipedia.

https://en.wikipedia.org/wiki/WNT4

Anonymous said...

"Female is not the default state. The fetus is undifferentiated until about week 8 and can go either way."

That's not correct. In the absence of SRY, the fetus becomes female. So, the default is, in fact, female.

Anonymous said...

There's a guy joke in there somewhere just trying to get out. The trouble is women have no sense of humor.


Obviously the sense of humor is part of the Y chromosome.

pat said...

The idea that women are superior because the X chromosome has more genetic material than the Y is pretty stupid.

Human genetics and every other kind of genetics involves discrete coding not analog coding.

When I taught Microsoft systems I told the students that the NT operating system was very, very different from the NT Server OS. And it was. But at installation time there was only a single byte that set then apart. That byte was a flag that set the installation on one path or the other. At the end they looked very different and each could do things that the other couldn't do. Sort of like the Robert Frost poem.

In fact since somatic genes are diploid and largely redundant the second X chromosome doesn't do much for you. But the Y chromosome has material available nowhere else.

Albertosaurus

Anonymous said...

That's not correct. In the absence of SRY, the fetus becomes female. So, the default is, in fact, female.

Except in those cases where a female to male sex reversal occurs, like the absence of WNT4.

Anonymous said...

In fact since somatic genes are diploid and largely redundant the second X chromosome doesn't do much for you. But the Y chromosome has material available nowhere else.

Indeed, males have all the genes needed to make males or females, but don't have a uterus.

Anonymous said...

The idea that women are superior because the X chromosome has more genetic material than the Y is pretty stupid.


Which is why it gets pushed on the science pages of newspapers.

Anonymous said...

So, what do you call an XX individual who has a uterus but no vagina, or an XX individual with stage 5 CAH and thus what looks like a penis and a scrotum?

What do you call an XY individual with androgen insensitivity, and thus a vagina but no uterus, but also external female looking genitalia?

Anonymous said...

"So, what can we do to add the "Alpha Male" gene to all the beta computer programmer and engineer types that deserve to reproduce so that Western civilization can go forward?" - they'll stop being programmers and start chasing skirts all day.