Two ge­net­i­cally iden­ti­cal long-tailed macaque clones have been suc­cess­fully bred by Chi­nese re­searchers

BBC Earth (Asia) - - Update -

A pair of pri­mate clones bred us­ing so­matic cell nu­clear trans­fer (SCNT), the tech­nique used to cre­ate Dolly the sheep more than 20 years ago, have been born at the Chi­nese Academy of Sciences in Shanghai.

The new­borns are just sev­eral weeks old and have been named Zhong Zhong and Hua Hua af­ter the Chi­nese ad­jec­tive ‘zhonghua’, which means Chi­nese na­tion or peo­ple. They are cur­rently be­ing bot­tle-fed and are de­vel­op­ing nor­mally com­pared to other mon­keys their age.

In SCNT, the nu­cleus is re­moved from an egg cell and is re­placed with a dif­fer­ent nu­cleus from another cell. The egg cell then merges with the im­planted nu­cleus and de­vel­ops into a clone of what­ever it was that do­nated the nu­cleus.

Pre­vi­ously, in sheep, mice and cows, adult donor cells have been used to cre­ate healthy clones. How­ever, adult pri­mate cells proved re­sis­tant to the tech­nique. The Shanghai team over­came this by us­ing donor cells taken from a macaque foe­tus.

While Zhong Zhong and Hua Hua are the first pri­mates to be cloned us­ing this tech­nique, pri­mates have been cloned in the past. In 1999, a rh­e­sus macaque called Tetra be­came the first pri­mate to be cloned, though this was achieved us­ing a sim­pler method called em­bryo split­ting. Here, the cells in the em­bryo are split af­ter reach­ing the eight-cell stage to cre­ate four iden­ti­cal two-cell em­bryos in a man­ner sim­i­lar to nat­u­rally oc­cur­ring twins.

The break­through will make it pos­si­ble to breed ge­net­i­cally uni­form mon­keys. This will en­able re­searchers to study pri­mates in un­prece­dented de­tail, as well as help with the de­vel­op­ment of drugs and ther­a­pies for use in hu­mans. “There are a lot of ques­tions about pri­mate biology that can be stud­ied by hav­ing this ad­di­tional model,” said Prof Qiang Sun. “This will gen­er­ate real mod­els, not just for ge­net­i­cally based brain dis­eases, but also can­cer, im­mune or meta­bolic dis­or­ders and al­low us to test the ef­fi­cacy of the drugs for these con­di­tions be­fore clin­i­cal use.”

The re­searchers are ea­ger to point out that they are fol­low­ing strict guide­lines for an­i­mal re­search set by the US Na­tional In­sti­tutes of Health, and accept that the sci­en­tific com­mu­nity should de­bate ac­cept­able lab­o­ra­tory prac­tices con­cern­ing the cloning of non-hu­man pri­mates. “We are very aware that fu­ture re­search us­ing non-hu­man pri­mates any­where in the world de­pends on sci­en­tists fol­low­ing very strict eth­i­cal stan­dards,” ex­plained co-au­thor Prof Mum­ing Poo.

They now plan to con­tinue im­prov­ing the tech­nique and ex­pect more macaque clones to be born over the com­ing months.

Ul­tra­sound scans of sur­ro­gate uteruses from the SCNT process. The uterus on the left con­tains no foe­tus, but the one on the right has been suc­cess­fully im­preg­nated and the foe­tus can be seen

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