On Wed, 06 Feb 2008 12:42:26 GMT, David Harper
<devnull@[EMAIL PROTECTED]
>
wrote:
>The three people involved contributed DNA as follows:
>
>Mother: 23 chromosomes, around 3 billion DNA "letters"
>Father: 23 chromosomes, around 3 billion DNA "letters"
>Egg donor woman: mitochondrial DNA, about 16,000 DNA "letters"
>
>The mitochondria are sometimes called the "power plants" of the cell
>because they produce ATP, a molecule that is an essential source of
>energy for all of the other chemical processes going on within a cell.
>
>The fact that they have their own DNA, independent of the nucleus of the
>cell, is intriguing, and has led biologists to hypothesise that the
>mitochondria are actually descendants of ancient bacteria which formed a
>symbiotic relation****p with other organisms early in the history of
>multi-cellular life on Earth.
>
>However, the mitochondrial DNA is tiny in comparison with the 46
>chromosomes that we inherit from our parents: 16,000 DNA "letters"
>compared to six billion. It is also tiny in terms of the number of
>genes it contains: a mere 37, compared to the estimated 20,000 to 25,000
>genes that are contained in the chromosomes.
>
>The mitochondrial DNA does not carry any of the genes for
>characteristics that we normally regard as inherited, such as hair
>colour, height, and so forth. In that sense, it doesn't make much of a
>contribution from a genealogical standpoint.
>
>However, it can, unfortunately, contain errors, and these can give rise
>to genetic defects in the same way as defective genes on the
>chromosomes. A mother with a genetic defect in her mitochondrial DNA
>would pass that on to all of her children, since we inherit our
>mitochondrial DNA solely from our mothers.
>
>The purpose of the research that was re****ted this week is to help such
>women to have healthy children. The donor woman would be someone
>without a defect in the mitochondrial DNA.
>
>I hope this helps to clarify things.
Thank you, yes it does help to clarify them.
But, if I understand you correctly, even if the children were healthy,
they
would still pass on defective mitochondrial DNA to *their* children?
--
Steve Hayes from Tshwane, South Africa
Web: http://hayesfam.bravehost.com/stevesig.htm
Blog: http://methodius.blogspot.com
E-mail - see web page, or parse: shayes at dunelm full stop org full stop
uk
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