From sheep to Human?

BJR browland at knox.edu
Mon Mar 10 03:59:38 EST 1997


>> The cloned individual is genetically 100% identical to the source of the
>> nucleus (this has been the mother, but could potentially be anyone).
>
>What do you mean by "mother"? The _genetic_ concept of "mother" is not
>applicable to cloning. Do you mean the birth-mother? I thought the lamb
>Dolly was brought to term in the uterus of another sheep, not the donor.
>Or do you mean the nucleus-donor? In the first case your statement would
>be simply wrong; in the second it would be (at best) a logical
>absuridity.

The article I first read on this said that the donor DNA came from the
birth mother. The correct Roslin article states otherwise. I was
misinformed.

>Also, not to be *too* nit-picky, but the clone will have the
>mitochondrial genotype of the egg-donor (which may well be its
>nucleus-donor, I suppose).

Thanks for pointing that one out. Your point is correct: the egg-donor
could have been the nucleus-donor, in which case, my original statement
would have been correct. However, having read the proper article, I stand
corrected.

This is an excerpt:
You have two different cells in nuclear transfer: an unfertilised egg and a
donor cell. The donor cells were obtained by culture of cells from sheep
embryos over a period of several months. In this way it was possible to
obtain many thousand genetically identical cells. The donor embryo was from
an all white breed: the Welsh Mountain breed. The recipients eggs were
recovered from Scottish Blackface ewes. By micromanipulation the
chromosomes were removed from the eggs before the nucleus of the donor cell
was introduced by cell fusion. --Roslin Institute

Ben





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