Are there men with YY chromosomes? The normal is XY determing male sex. If so what are these man like? I tried searching the archive, but found nothing.
Carl
your mom contributes your x chromosome. ova only contain x chromosomes. Your dad contributes either an x or a y chromosome, resulting in a female or male child respectively. Sometimes, rarely, a woman becomes pregnant without sperm. The result is always a girl with a single x chromosome, probably inadequate sexual characteristics (a dimple rather than a vagina, for example) and unable to reproduce. In other rare circumstances, probably due to two-headed sperm or sperm cells that did not become separated properly into x and y bearers, an ovum will become vertilized with a sperm that contains two y or an x and a y chromosome. the resulting infant will exhibit certain characteristics. An XYY male (the kind I think you are asking about) will have an exaggerated masculinity–lots of hair, lots of muscle mass, poor impulse control. These guys are dangerous and may find themselves in prison early and often. They’re often retarded. XXY males would probably be hermaphroditic, exhibiting sexual characteristics of both males and females–testicles, vagina, oversized penislike clitoris, breasts, facial hair, and so on. At some point in their lives, they would have to make a decision whether to live as men or women and modern medicine can bring surgery and implants to bear to aid them in their masquerade. Hermaphrodites are generally sterile. In an extreme case, where there is a descended, functioning testicle and a functioning ovary, it would not only be possible for the hermaphrodite to bear children and inpregnate women, but he would also be able to impregnate himself or herself.
I want to stress that most xyy males aren’t criminals or retarded. I probably painted a pretty ugly picture above. There might be a slight tendency toward poor impulse control and some xyys are retarded, but new research suggests that retardation among xyy males is as rare as among xy males. So if you are xyy, don’t take it as a license to turn into the incredible hulk. You’re probably a little taller, a little more energetic, a little quicker to anger, but you can control yourself.
some links:
http://www.diseasesigns.com/rarediseases/links/xyysyndrome.html
http://www.urologychannel.com/maleinfertility/causes.shtml
http://www.karger.ch/journals/CCG/ccg78-2.htm
[Moderator’s note: I shortened the link. -manhattan
[Edited by manhattan on 07-15-2000 at 12:35 PM]
I knew an XXY girl in grade school. She was extremely androgenous. It was almost impossable to identify her gender. She was also a tomboy, and got in trouble quite often.
According to my high school biology textbook, an embryo with a lone X (referred to as ‘XO’) would not survive. Perhaps you’re thinking about an XXX combination. XXX is called a ‘meta-female’. Such girls are short, sexually immature, and usually sterile. Conversely, meta-males (XYY) are described as ‘usually normal.’
Get out of here! Has there ever been a recorded instance of this happening?
Cecil Adams on parthenogenesis. I’m unaware that this has been documented to occur to humans. As to the other stuff, I’ll leave it up to the members (heh) to comment on two-sex self-induced pregnancy.
XO females certainly can survive. One in two thousand live female births has this genotype. The disorder is called Turner’s Syndrome or Gonadal Dystenesis. Symptoms normally include the lack of a menstural flow, low estrogen levels, serility, and thick neck. There is also often cardiovascular, ear, eye, and kidney problems. IQ is normal.
XXY is known as Klinefelter syndrome. All are phenotypically male. One in one thousand newborn males have this genotype. They suffer reduced fertility, but not sterility.
XYY is male. About 1 in 1000 newborn males have this genotype. Average IQ is rather low, but not retarded (85-90). They are not infertile, and their offspring are usually normal.
YO genotype is not viable. At least one X-chromosome is required for development.
I told the XXY to go F itself. Much to my surprize, it complied.
XO
Lokk up the Black Dahlia murder case for a good example.
bibliophage mentioned why YO is inviable. If you had a YY (which would take some doing) it would also be inviable, for the same reason. You need an X. There’s important operating system info on there.
As an interesting aside, this discussion reminds me that (almost) all calico cats are female. This is because the gene for coat color is carried on the X chromosome, and a cat with two Xs might get conflicting signals and turn out calico.
But there are a very few male calicos, who have the XXY combination. I’ve read that they’re sterile.
Don’t forget the XXXY (Nondisjunction from both mother and father). I don’t recall what it is, but it’s possible.