I know that the Y chromosome is only found in males,but is there any
type of dna only found in females.

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Request for Question Clarification by knowledge_seeker-ga on 04 Dec 2003 06:59 PST

Hi arkin,

Are you talking about genes or chromosomes?

Humans have 23 pairs of chromosomes. Of those, one pair is made up of
X and Y, and yes, you are correct, only males have the Y chromosome.
In men the pair looks like XY and in women the pair looks like XX. All
of the other chromosomes are shared by both sexes.

On each chromosome there are hundreds or even thousands of genes. How
those genes are combined on the chromosomes is what makes up our DNA.

There is however one special type of DNA that, while present in both
males and females, only gets passed to the next generation by females.
In other words, both males and females get it from their mothers, but
the male can't pass it on.

If you'd like information on that as your answer, let me know by
posting a clarification.

Thanks!

-K~

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Clarification of Question by arkin-ga on 05 Dec 2003 19:54 PST

Thanks for responding.I was talking about genes.

The CHD-W gene (in birds) is only found in females.

Apologies to Knbowledge_seeker if I'm spoiling something, but I guess
what they are referring to is mitochondrial dna.
The mitochondria are the power generators of the cell. They are
present in both the egg and the sperm, but since male dna is injected
on its own without any other parts of the male gamete, only the
maternal mitochondria make it through to the child.
It is postulated that the mitochondria represent the remains of
another organism that has merged into a symbiotic relationship with
our human cells (creepy!).

The Endosymbiotic theory (note form)
http://members.cox.net/tmccabe/calendar/docs/MitochondrialDNA.doc

Mitochondrial DNA and the evolution of humanity
http://www.actionbioscience.org/evolution/ingman.html

Mitochondrial DNA in forensics
http://www.mitotyping.com/dna.htm