He is best known for his pioneering research in nuclear transplantation
and cloning, discovering that mature cells can be converted to stem cells.
The viability of late morulae and blastocysts produced by nuclear transplantation
Germinally transgenic tadpoles were produced by restriction enzyme-mediated integration nuclear transplantation
according to Kroll and Amaya (1996), with the following modifications: sperm was purified by centrifugation on a two-layer discontinuous Percoll (Sigma) gradient before the permeabilization step, which was performed with digitonin (Sigma) instead of lysolecithin.
That bill actually allowed the human cloning procedure, calling it "nuclear transplantation
," but banned two things: (1) "implanting or attempting to implant the product of nuclear transplantation
into a uterus or the functional equivalent of a uterus"; and (2) maintaining such a cloned human embryo for "more than 14 days from its first cell division," not counting time spent in a freezer.
The new legislation, which was referred to the Committee on the Judiciary chaired by Specter, would allow embryonic stem cell research' known as somatic cell nuclear transplantation
, to proceed under strict oversight from the federal government.
92) Human cloning was defined as "implanting or attempting to implant the product of nuclear transplantation
into a uterus or the functional equivalent of a uterus.
McGreevey (D) last month signed a law that permits the use of research involving the derivation and use of human embryonic stem cells, human embryonic germ cells, and human adult stem cells from any source, including somatic cell nuclear transplantation
or "therapeutic cloning.
The bill states that "the policy of the state shall be that research involving the derivation and use of human embryonic stem cells, human embryonic germ cells, and human adult stem cells from any source, including somatic cell nuclear transplantation
, shall be permitted, as specified.
The group recognized the potential of therapeutic cloning in medical research: "The scientific and medical considerations that justify a ban on human reproductive cloning at this time are not applicable to nuclear transplantation
to produce stem cells," the academy report said.
In nuclear transplantation
in animals, researchers place DNA from an existing animal inside an egg they've stripped of its own DNA.
Insignificant as they appeared, the specks were precious because they were, to our knowledge, the first human embryos produced using the technique of nuclear transplantation
- otherwise known as cloning.