From: taquilla@SPAMOFF.erols.com (Tracy Aquilla)
Subject: Is Dolly really a CLONED Sheep? Maybe NOT!
Date: Wed, 11 Feb 98 02:15:13 GMT
This is peripherally related to agriculture, and lots of fun anyway.
Has anyone seen the latest issue of Science (Jan 30 '98, vol. 279 No. 5351)?
It has a couple of interesting articles indicating that it has not yet been
proved that Dolly is genetically identical to the donor sheep (i.e. THERE IS
NO PROOF THAT SHEEP HAVE BEEN CLONED!). Anybody want to bet these articles
get the same level of press coverage? People ought to analyze the facts for
themselves, instead of believing something just because it is on the evening
In fact, the donor ewe was pregnant and it is therefore quite possible that
Dolly was derived from an embryonic cell (no great feat there at all -
embryo transplant is old hat even in humans). Unfortunately
(conveniently?), no DNA samples were taken from the paternal parent or the
embryo itself, and the embryo aborted and was destroyed, so definitive
testing is now impossible. Although no DNA fingerprints have been made to
confirm the genetic identity of Dolly and the donor, such experiments are
currently in progress. I'd say lacking such data, the conclusion was
premature to say the least. But it did make headlines!
Furthermore, the alleged result of the experiment has not been able to be
repeated. Everyone I know who is up to date on this technology is highly
skeptical. DNA is permanently modified during early development, and upon
differentiation of cell and tissue types, many essential genes are
rearranged and/or deleted, thus eliminating the totipotency of nuclei
obtained from adult tissues. Therefore, most likely explanation for Dolly's
existence is that she was derived from an embryonic cell, rather than a
differentiated somatic cell (i.e. adult mammary tissue).
I don't consider myself an expert in development, but I am well quite versed
in molecular genetics, and based on the above, I seriously doubt that
cloning an adult mammal is possible. I certainly won't believe it until I
see some credible evidence. So far, there is none!
Considering these facts, I think our Congress is wasting time with these
silly anti-cloning bills. But that is probably by design. ;-) They sure
know how to pick their battles in DC.