Is it possible to manipulate Chromosomes so a newly fertilized egg gets 2 Y chromosomes, and if so, what is the sex?
I dont know what if anything would come of that, but I believe Downs Syndrom is due to an extra Y chromosome.
Down syndrom is an extra chromosome, but not on the 23rd pair of chromosomes (where sex is determined.) Its an extra on the 15th pair I believe. YY doesn’t occur as far as I know, but the Y chromosomes don’t contain any information anwa. So it would probably be either dead, or whatever has 44 chromosomes. Just a WAG on that last sentence though.
Actually Down’s Syndrome is caused by an extra copy of chromosome 21, which is thought to be caused by a copy error in the mother’s ovum. The OP is an interesting question though, assuming that you could combind two sperm cells and implant the resultant cell in a female.
YY = dead
I think it has to be X-something.
Well, an egg is always an X-chromosome. A female is not capable of producing a Y-chromasome, since they don’t have any to begin with. Maybe it’s possible to artificially create an egg with a Y chromosome, but I don’t know.
This Web site addresses the YY:
http://www.mansfield.ohio-state.edu/~sabedon/biol1125.htm
Autosome
- An autosome is a eucaryote chromosomes other than a sex chromosomes.
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Sex chromosome [X chromosome, Y chromosome]
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Eucaryote chromosomes of many species (of, particularly, animals) may be distinguished into two general categories: Those that are involved in the determination of gender (sex chromosomes) and those that are not (autosomes).
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In humans, the female gender is determined by the absence of a Y chromosome and the presence of an X chromosome while the male is determined by the presence of a Y chromosome. Since females have only X chromosomes, the only combination of chromosomes that normally occurs is XX (i.e., female) and XY (i.e., male).
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Note that a human lacking an X chromosome is also inviable since the X chromosome carries a number of valuable genes (i.e., just YY and just Y are not viable). The same cannot be said for the Y chromosome which is of value only in the determination of gender.
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Note that not all species employ chrosomal (i.e., genetic) differences to determine gender. In fact, there are a whole range of strategies by which gender is determined in the natural world, and it is not unheard of for organisms to switch gender during normal, adult maturation.
YY= impossible. Since females are XX, all ova carry the X chromosome. Ys come from XY males. (Meiosis is the production of reproductive cells that cuts the chrosome pairs in half- XX females split into X and X, XY males into half X and half Y). I think any Y (XY, XXY) would be male, so no female could have an ovum with a Y.
YY is a supermale. Some species can switch genders depending on the situation. So if there is no female around a XY male can become a XY female. The offspring would be 25%XX 50%XY and 25%YY in other words 50% male and an additional 25% supermale.
Also I’ve heard that humans can have a XY female and XX male. It all depends on hormone levels while the unborn baby is developing.
whoa, triple post.
I suppose it would be possible for an ova to lack a sex chromosome, and be fertilized by a diploidal sperm with two Ys, leading to a YY. But that wouldn’t work, due to the necessary info on the X, as Snoooop points out.
A human XY female would occur if the testes determining factor which would normally lead to maleness is absent or nonfunctional. Assuming that an XY female is fertile, I suppose it could pass its Y along with the Y of an XY male to create a YY, which would likely be aborted before anyone realized there was a pregnancy.
Got a little mixed up - it should read 50% male and an additional 50% supermale.
Check out:
http://www.upd.edu.ph/~updinfo/archives/novdec2000/tilapia.htm
and
http://www.fishgen.uko.com/10FAQ.htm#What%20is%20a%20supermale?
There is a phenomenon called “miotic non-disjunction” which occurs when the gamete is created. It causes the sperm or egg cell to have both halves of a pair of chromosomes. A human zygote from such a gamete can survive, and be born normally. The person developed from that zygote could have the pattern XXY, or XXXY from the case where the disjunction occurs in both parents. All of these conditions are relatively rare. The person is generally physically male, to all but genetic or, in some cases very close internal examination.
The case YY could not occur because the development of female reproductive organs requires an XX pair. While it is within the realm of theoretical possibility that an adult XXY human could develop as a female, and experience the specific non-disjunction that would provide a Y gamete, which was then combined with a Y male gamete, the apparent odds are drastically reduced by the overwhelming factors of probable sterility in the mother, low viability in non-disjoined gametes, and the
similar deficits in viability of all “mosaic” chromosome zygotes.
How that unfortunate person would present physically is impossible to say.
Tris
-------------------------------“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.” ~ Albert Einstein ~
from the 2nd above cite:
I just can’t get this right - YY supermale and XX female yeilds 100% male. It’s the supermale - cross gendered male that yeilds trouble
I was told that YY is not viable AT ALL in humans, and, indeed, in most mammals. (This was in my genetics class, 2nd year university).
I’ve heard of the XYY Supermale…I figure, somehow subtract the
X chromosome from the newly formed zygote.
What is a supermale? Physically or psychologically, I mean.
There’s some confustion here. A YY “supermale” is not found in humans. As has been stated, a YY human, even if we could figure out how to make one, would die well before birth, because the X chromosome contains vital genes. The “supermale” term is applied to other species in which genetic studies have been done. I know it’s used in Drosophila genetics, although their sex determination patterns are more complicated than ours.
Also, someone stated that the Y chromosome has no genetic information. This is incorrect. It does have genes on it, including the sex-determining region, which is what actually causes maleness. That, in fact, is how you could get an XX male - if that region had been transposed onto an X chromosome. Simlarly, if it was missing from a Y chromosome, you could get an XY female.
Incidentally, in other species, sex determination mechanisms vary widely. In many birds, for instance, XX is male, while XY is female. In many many other species, males and females are genetically identical, and gender is determined by some other method. Crocodile gender, for instance, is decided by the temperature of the egg. And there’s a marine annelid worm where it depends on where the larva lands. If it lands on bare ground, it becomes a female. If it lands on a female, it becomes a male. Pretty much any system you could imagine is used somewhere.
So do animal YYs have any phenotypic differences from XYs, or is it only that they produce only males (when XX is female, XY is male, etc.)?
I’m a supermale, but only in phenotype, not in genotype. At least, that’s what the ladies tell me… 