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Boy interrupted: Y-chromosome mutations reveal precariousness of male development
Biology News Net ^ | September 2, 2013 | NA

Posted on 09/16/2013 3:32:09 PM PDT by neverdem

The idea that men and women are fundamentally different from each other is widely accepted. And throughout the world, this has created distinct ideas about which social and physical characteristics are necessary in each gender to maintain healthy human development.

However, social revolutions throughout the last century have challenged traditional ideas about not only which traits are normal and necessary for survival, but also how humans acquire them. Thanks to a new study from researchers at Case Western Reserve University, science is continuing the charge.

By studying rare families in which a daughter shares the same Y chromosome as her father, Michael Weiss, MD, PhD, and his colleagues at the university's School of Medicine have determined that the pathway for male sexual development is not as consistent and robust as scientists have always assumed.

A team led by Weiss, chairman of the Department of Biochemistry, the Cowan-Blum Professor of Cancer Research, and a professor of biochemistry and medicine, has published a study in the Proceedings of the National Academy of Sciences that examines the function of the SRY gene. This gene is responsible for initiating the process that leads to male development.

"A general principle of developmental biology is that evolution favors reliability," Weiss explained. "Robust switches ensure that our genetic programs give rise to a consistent body plan to ensure that babies have one heart, two arms, ten fingers, and so forth."

Traditional viewpoints emphasize the uniformity of this process. The new research indicates that male sexual development is less stable than other genetic programs.

In fetal development, a gene located on the Y chromosome, called SRY, begins the process that leads to male development. All fetuses initially develop with female tissues, no matter what the sex will be at birth, so the master switch is responsible for initiating the transformation of female tissues into male tissues. From there, the testes develop and produce testosterone, which eventually forms the male's external genitalia.

The university's study employs mutated SRY genes shared by a father and a sterile XY daughter. Females usually develop with an XX pair, but, in these families, the father instead produced a daughter with an XY pair. This occurs during fetal development when the SRY gene's master switch fails to trigger. Internal female tissues, such as the uterus and fallopian tubes, continue to develop but are dysfunctional and infertile.

"Yet the father has the same Y chromosome and the same mutation as the daughter," Weiss pointed out. "And since he is a fertile male, we know that the switch must be poised right at its edge."

The team decided to measure the biochemical threshold of the SRY master switch.

"Our expectation was that we'd find that a factor of 100 or more—a severe insult to the Y-encoded switch—was necessary to alter development," Weiss said. "But what we found was that the SRY threshold, as probed in father-daughter pairs, is only a factor of two."

Therefore, human males actually develop near the edge of sexual ambiguity. This means that, unlike the robust genetic programs which develop other essential processes like heart function, the SRY gene master switch is particularly vulnerable to change. It only takes a slight deviation from the normal process to dramatically alter fetal sexual development.

Given the importance of sexual reproduction to the survival of a species, why do human SRY genes function so close to the boundary of infertility? The idea of an unreliable master switch might appear paradoxical, but a growing body of research suggests that it might be an evolutionary necessity.

Extensive studies of gender-associated styles of childhood play and the acquisition of social competencies by Dr. S. Baron-Cohen and colleagues at Cambridge University (UK) have highlighted the long-term effects of testosterone secretion by the fetal testis. Testosterone influences the patterning of the male brain during a critical window in human development.

And it is the SRY gene that sparks the genetic program leading to the formation of testes and the production of fetal testosterone.

"We have this tenuous switch on the Y chromosome, and we anticipate that its gift to humanity is variability in the pathway of male development from its earliest stages," Weiss said. "The essential idea is that our evolution has favored a broad range of social competencies. In prehistory, this range would have given a survival advantage to communities enriched by a diversity of gender styles."

In fact, certain aspects of modern history seem to parallel this idea.

Susan Case, PhD, a professor of organizational behavior at Case Western Reserve Weatherhead School of Management, who was not involved in the study, agreed with Weiss's argument and noted that "diverse mixes of people offer more varied perspectives, more ideas and solutions, and more challenges to long-accepted views." In the corporate world, for example, these differing styles increase creativity and problem solving, especially within a group.

The implications of Weiss's research suggest that elements of human culture, which had been assumed to be psychological or cultural, may be biological, instead. Therefore, human evolution would not have been dependent on consistency and homogeneity, but on their exact opposite.

Source : amanda.petrak@case.edu


TOPICS: Culture/Society; News/Current Events
KEYWORDS: maledevelopment; sry; ychromosome
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Inherited human sex reversal due to impaired nucleocytoplasmic trafficking of SRY defines a male transcriptional threshold
1 posted on 09/16/2013 3:32:09 PM PDT by neverdem
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To: neverdem

I am too stupid to get what they are talking about


2 posted on 09/16/2013 3:38:51 PM PDT by yldstrk (My heroes have always been cowboys)
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To: neverdem
The idea that men and women are fundamentally different from each other is widely accepted.

It has always been a universally accepted fact until the universities lost their collective minds.

3 posted on 09/16/2013 3:40:33 PM PDT by Jeff Chandler (Don't blame me for McCain.)
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To: yldstrk
I am too stupid to get what they are talking about

No you're not. It's likely just more pseudo-"science"; politics masquerading as medicine. I believe very little of what today's "scientific" institutes put out anymore.

Most nonsense sounds like gobbldy gook.

4 posted on 09/16/2013 3:42:19 PM PDT by fwdude ( You cannot compromise with that which you must defeat.)
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To: neverdem

Even if true, be sure that 99.9999% of men who say they are really women do NOT match this scenario one single bit.


5 posted on 09/16/2013 3:43:48 PM PDT by fwdude ( You cannot compromise with that which you must defeat.)
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So I guess I’m an evolved woman... here me roar!


6 posted on 09/16/2013 3:45:31 PM PDT by Gene Eric (Don't be a statist!)
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To: Gene Eric

And hear me roar too!


7 posted on 09/16/2013 3:45:56 PM PDT by Gene Eric (Don't be a statist!)
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To: neverdem

Don’t know about that. But I do have the SRW genes - Super Reactive Willy. Carlos Danger and I have registered the trademark “BoingMaster” as part of our marketing campaign.


8 posted on 09/16/2013 3:46:40 PM PDT by USMCPOP (Father of LCpl. Karl Linn, KIA 1/26/2005 Al Haqlaniyah, Iraq)
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To: neverdem

"...???....yep, male"

9 posted on 09/16/2013 3:53:04 PM PDT by Doogle (USAF.68-73..8th TFW Ubon Thailand..never store a threat you should have eliminated))
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To: yldstrk

They are saying this is why Rosie O’Donnell has hair all the way down her back and chest.


10 posted on 09/16/2013 3:59:56 PM PDT by MadMax, the Grinning Reaper
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To: neverdem

“The essential idea is that our evolution has favored a broad range of social competencies. In prehistory, this range would have given a survival advantage to communities enriched by a diversity of gender styles.”

Oh, no! I call bull sh!t.

“...diversity of gender styles...” is another way of creating, out of thin air, a BIOLOGICAL excuse for the existence of homosexuality.


11 posted on 09/16/2013 4:06:29 PM PDT by SatinDoll (NATURAL BORN CITIZEN: BORN IN THE USA OFCITIZEN PARENTS)
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To: yldstrk
I am too stupid to get what they are talking about...

No you aren't. It's just a little obscure. The idea is that something in the Y chromosome doesn't turn an embryo into a male until well into the development of the embryo, and in this rare case it doesn't get switched on at all and you have what is morphologically a female - breasts, female hormones, etc - actually carry the chromosomes for a male. She's sterile as a result. But she has, in the single X chromosome she got from her mother, enough genetic information to form a nearly complete female.

Fascinating stuff. It is exquisitely uncomfortable for the supporters of abortion to contemplate just how much a fetus does develop in how little time. Undifferentiated tissue it is most certainly not.

Somewhere on that Y chromosome is the explanation for why only males attempt to light farts with fireworks. I would hate for future generations to be denied that important step in the evolution of our species.

12 posted on 09/16/2013 4:10:37 PM PDT by Billthedrill
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To: Doogle

#9 That looks exactly like my cat (in HER younger years).
If she tried that now... well... it wouldn’t be pretty.


13 posted on 09/16/2013 4:12:55 PM PDT by workerbee (The President of the United States is DOMESTIC ENEMY #1)
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To: neverdem

So as I understand this, I was a female, but I got lucky and grew junk. LOL


14 posted on 09/16/2013 4:13:04 PM PDT by Gator113 (The mighty Bear ate the cowardly rat. Obama must resign.)
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To: SatinDoll

I’m with you. I think they took something that could be scientifically correct and steered off into the PC realm.


15 posted on 09/16/2013 4:14:27 PM PDT by workerbee (The President of the United States is DOMESTIC ENEMY #1)
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To: yldstrk

>>>I am too stupid to get what they are talking about>>>

LOLZ! I’m so glad I’m not the only one.


16 posted on 09/16/2013 4:17:49 PM PDT by kitkat (STORM THE HEAVENS WITH PRAYERS FOR OUR COUNTRY.)
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To: Jeff Chandler

Have you ever noticed that women have a sixth sense that they are being “checked out”. Being old and ugly but not dead, I am amazed how a woman will look around when a guy is admiring her attributes stealthily..


17 posted on 09/16/2013 4:18:33 PM PDT by Little Bill (A)
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To: yldstrk; All

I think stuff in OP is fact-laced conjecture, aka scientific-sounding sophistry, intended to blur distinctions between male and female.


18 posted on 09/16/2013 4:18:37 PM PDT by Amendment10
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To: Jeff Chandler

Have you ever noticed that women have a sixth sense that they are being “checked out”. Being old and ugly but not dead, I am amazed how a woman will look around when a guy is admiring her attributes stealthily..


19 posted on 09/16/2013 4:18:45 PM PDT by Little Bill (A)
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To: neverdem

Among plants and animals, species tend to increase their number of chromosomes when they want greater diversity and adaptability. They tend to decrease their number of chromosomes when they are trying to save energy.

The human species seems to be trying to decrease our number of chromosomes. This seems to be why we have 46 pairs, but other primates: gorillas, chimpanzees and orangutans have 48 pairs.

In any event, this may explain the ‘Y’ chromosome of males. Originally, it was likely an ‘X’ chromosome, but one of its ‘arms’ or ‘legs’ was broken off and no longer copied.

Eventually, the ‘Y’ chromosome is expected to fail. But a replacement is waiting in the wings, as it were. The ‘X’ sex chromosome, the female chromosome, seems to be weakening. A common cause of birth defects today is called “Fragile X Syndrome”, in which one of the ‘arms’ or ‘legs’ of the ‘X’ sex chromosome is damaged or even broken.

So the ‘Y’ chromosome fails, and is replaced by a new ‘Y’ chromosome, and another ‘X’ chromosome replaces it as a sex chromosome.


20 posted on 09/16/2013 4:20:20 PM PDT by yefragetuwrabrumuy (The best War on Terror News is at rantburg.com)
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