Males more prone to cloning

[Wise Young]

Hmm, this is interesting. Why should male nuclei be more suitable for cloning?

http://www.newscientist.com/article/...o-cloning.html

Males more prone to cloning

* 22:00 12 February 2007
* NewScientist.com news service
* Peter Aldhous

Cloning researchers who wish to boost their success rates should try using male cells, researchers say. The advice is based on a new study which showed that mouse embryos created from male adult cells were more than three times as likely to develop to term as those created from female adult cells.

Cloning an adult animal usually involves putting the nucleus from an adult cell into an egg that has been stripped of its chromosomes. However, progress has been hindered by the fact that "reprogramming" adult nuclei in this way has very low success rates.

To get around this problem, a team led by Peter Mombaerts and Elaine Fuchs at Rockefeller University in New York, US, tried using adult skin stem cells, which are less differentiated and so should be easier to reprogram.

The success rate was still very low, but they did find that 5.4% of embryos created from male cells developed to term, compared with 1.6% for comparable cells from females.

More tests are now needed to confirm whether this sex bias holds true for other cell types.

[cljanney]

Originally Posted by Wise Young

Hmm, this is interesting. Why should male nuclei be more suitable for cloning?

Combat Drones!

[Wise Young]

Originally Posted by cljanney

Combat Drones!

How about sex machines? Those who get their sperms to the eggs will survive while those who just get their licks in will become extinct.

The question is actually very interesting from a biological point of view. When one does somatic nuclear transfer into an egg, one is tearing the nucleus from its nest of cytoplasm and putting it into the den of another. Why should the male nucleus fare better than a female nucleus?

What is the major difference between a male and female nucleus? There is only one difference. A female nucleus as two X-chromosomes while the male nucleus as an one X and a Y-chromosome.

Genetic regulation of the female nucleus is definitely more complicated than the male nucleus. The female nucleus must turn off parts of one X-chromosome in order to survive. Most females are chimeras, i.e. they have patches of cells, half of which express one X-chromosome and the other half express the other X-chromosome.

Wise.

[adi chicago]

if adam was first ...eve should say...thank you.

[Lindox]

Chimeras? Dr. Wise don't you like girls anymore?

[Wise Young]

Originally Posted by Lindox

Chimeras? Dr. Wise don't you like girls anymore?

Lindox, I am fascinated by girls. Can't you tell?

I have been fascinated ever since I learned that cats that are calico (almost always female) because of a gene carried on one of the X-chromosomes of the cat and that the mottled color of calico cats results from skin cells expressing only one or the other chromosome. The implication of this statement is that I wasn't fascinated by girls before... hehe.

The story gets better. Calico cats have white but tortoiseshell cats have a "ginger" color, caused by the O gene. Some cats are "brindled torties" while others are "patched torties", due to the timing of X-chromosome deactivation. Presumably, the later that it happens, the smaller the patches and the earlier it happens, the bigger the patches. There are abyssinian (cinnamon) cats that involve a non-sex-linked gene.

If you clone a tortoiseshell cat you will end up with a cat of one or the other color and not a tortoiseshell clone. This is because the nucleus that you have transferred probably will have an already inactivated X-chromosome and therefore will express only one of the colors.

http://www.messybeast.com/tricolours.htm
http://www.messybeast.com/mosaicism.htm

Wise.

[Lindox]

I know what you mean. I became fascinated with boys after learning of the male fly's superior visual system. LOL.