Men only have the Y-chromosome.Since it is passed from dad to son, do all Y have the same genetic code?

Question

I tried this question on some learned friends with this result: seems logical; if mitochondrial DNA comes from the mother to daughter its ok for the y to come from the dad; can't be the same y due to diversity; what's a chromosome; asking why (Y) is a man thing. Here is a problem. Mitochrondia ALSO enter the egg as part of the sperm cell .No real problem, unless you are hung-up on mother to daughter transfer of M-DNA. Because which ever human sperm fertilized the first human egg the M-DNA was forever mixed.Yes, to the female offspring but ALSO to a male kid. Each of which continued to pass on M-DNA to a fertilized egg/zygote. It should be noted that " M" of the M-DNA is not "maternal" but "M"itochondrial.And IT didn't come from a MOTHER somewhere in Africa umpteen years ago. You could just as well trace the paternal mutation rate in subsequent generations since the sperm number of M-DNA is tiny compared to the egg .What say ye? Please a reference, if you know of any.

Answer 1

Mitochondria are only in the egg, not in the sperm. The mitochondrial DNA replicates like a bacterium, asexually. So there is little variation over the generations.

The Y chromosome undergoes meiosis with the rest of the chromosomes. Because of crossing over, variation occurs in the Y chromosome just like the other chromosomes.

Answer 2

No mitochrondria come from the sperm cell. Yes, there is mitochrondria in the sperm, but none enters the egg cell upon fertilization.Only the head does that contains the genetic information. The mitochondria are located in a compartment (for lack of a better word) directly behind the head of the sperm, called the midpiece. Therefore, mitochondrial DNA is only from the mother.

Answer 3

Inheritance of paternal mitochondria is thought to be rare in human beings. See the link.
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Yes, male heritage can be traced through the Y chromosome. Not all Y have the same genetic code, because of accumulated mutations and chromosomal changes. It is these changes that can be used to trace paternal heritage.

Answer 4

Almost; Here is a good explaination:
http://www.answers.com/topic/y-chromosome?cat=health
The mitochondria of the sperm are destroyed. Here is another good explaination:
http://www.sciam.com/article.cfm?articleID=0008F0A0-8234-1C6D-84A9809EC588EF21&pageNumber=1&catID=2

Answer 5

yes all y's are the same, but almost everything but sex is determined by the X chromosomes