s finding te
lls us 
something a fou
t the nature of the genome of adult cells -- the
cells are not very labile and difficu
wo clone. This is im
portant to know, if adult cells areboing to be cloned for personal
ed cell therapy," says Jaenisch. "This finding tells us something a fout the nature of the genome of adult cells -- the cells are not very labile and difficu wo clone. This is important to know, if adult cells areboing to be cloned for personaled cell therapy," says Jaenisch.
Therapeutic cloning involves removing the nucleus, or the genetic command center, of an egg and replacing it
with the nucleus from an adult donor
ell.
Ideally, the egg resets the developmental clock of the nucleus back to a state compatible with early embryonic growth.
This ball of cells growing in culture gives rise to embryonic stem (ES) cells that genetically match the donor and have the potential to become any tissue in the body. In theory, these ES cells may be used to treat diseases, such as diabetes or spinal cord injury, without the complications of organ rejection.
Scientists have known for some time that cloning using ES cells is much more efficient than using adult cells, probably 10-fold more efficient. This makes sense because ES cells are at the earliest developmental stage and have the potential to become all the cells that make up an organism.
But researchers didn't know if cloning could set the clock back for mature adult cells, such as skin or mammary cells, which are committed to a specific function.
Alternatively, researchers speculated that rare, adult stem cells, which are further along the developmental path than ES cells but not yet committed to a specific function, were the ones creating the clones.
This was a difficult puzzle to solve since most adult cells don't have stable genetic markers that can be tracked from the donor nucleus to the resulting clone.
Immune cells called B cells and T cells are an exception -- when these cells reach maturity, special genes, called immunoglobulin genes, are permanently shuffled. This rearrangement process allows these immune cells to produce the many unique antibodies and receptors necessary to recognize and fight the plethora of pathogens we encounter from a limited number of genes.
The Jaenisch lab took advantage of these "unique gene signatures" and used nuclei from adult B cells and T cells to create clones. Where other groups had failed in creating clones from these immune cells, Hochedlinger succeeded by using a new two-step cloning process.
They first created cloned mouse embryos by transferring the nucleus from either a B cell or a T cell into a mouse egg that was devoid of its own nucleus. Instead of implanting the cloned embryos into the womb of a surrogate mouse at this point, the embryos were grown in tissue culture to make ES cells. zDatingbikini Mangas En Map 37 Dating Bikini Adult Stem Cells Likely The Ones That Are Cloned Datingbikini Mangas En Map 37 Dating Bikiniy Bikini Dating gDatingbikini Mangas En Map 37 Dating Bikini Adult Stem Cells Likely The Ones That Are Cloned Datingbikini Mangas En Map 37 Dating Bikinit Bikini Escort Girls