Sci­en­tists urge halt to Chi­nese ‘edit­ing’ of hu­man em­bryos

The China Post - - LIFE - BY KERRY SHERI­DAN

Global sci­en­tists on Thurs­day re­newed calls to halt con­tro­ver­sial re­search to ge­net­i­cally edit hu­man em­bryos af­ter a Chi­nese team pub­lished de­tails of a break­through at­tempt in this new fron­tier in science.

First re­ported by Na­ture News on Wed­nes­day, the pa­per by Jun­jiu Huang, a gene-func­tion re­searcher at Sun Yat-sen Uni­ver­sity in Guangzhou, and col­leagues ap­pears in a lit­tle known on­line jour­nal called Pro­tein and Cell.

In the pa­per re­searchers de­scribe how they changed the genomes of em­bryos ob­tained from a fer­til­ity clinic.

The em­bryos could not have re­sulted in a live birth be­cause they had an ex­tra set of chro­mo­somes af­ter be­ing fer­til­ized by two sperm.

Re­searchers “at­tempted to mod­ify the gene re­spon­si­ble for beta-tha­lassemia, a po­ten­tially fa­tal blood dis­or­der, us­ing a gene-edit­ing tech­nique known as CRISPR/Cas9,” said the re­port in Na­ture News.

The re­searchers in­jected 86 em- bryos and waited 48 hours for the mol­e­cules that re­place the miss­ing DNA to act.

Seventy-one em­bryos sur­vived, and 54 of those were tested.

Re­searchers found that of those only 28 were “suc­cess­fully spliced, and that only a frac­tion of those con­tained the re­place­ment ge­netic ma­te­rial,” said the re­port.

“If you want to do it in nor­mal em­bryos, you need to be close to 100 per­cent,” Huang was quoted as say­ing.

“That’s why we stopped. We still think it’s too im­ma­ture.”

Un­in­tended Mu­ta­tions

Even more con­cern­ing were the “sur­pris­ing num­ber” of un­in­tended mu­ta­tions that arose in the process, at a rate far higher than seen in pre­vi­ous gene-edit­ing stud­ies us­ing mice or adult hu­man cells.

Such mu­ta­tions can be harm­ful, and are a key rea­son for con­cerns raised in the sci­en­tific com­mu­nity ever since ru­mors of the Chi­nese team’s re­search be­gan cir­cu­lat­ing ear­lier this year.

Crit­ics say the science could have un­known ef­fects on fu­ture gen­er­a­tions, and could open the door to a new era of eu­gen­ics by al­ter­ing hu­mans so they carry de­sir­able traits.

‘Sig­nif­i­cant im­pli­ca­tions’

In re­ac­tion to the re­port, the Al­liance for Re­gen­er­a­tive Medicine re­newed its call for a halt to the re­search, ac­cord­ing to an email sent to AFP.

“Given the sig­nif­i­cant safety and eth­i­cal im­pli­ca­tions of mod­i­fy­ing the DNA of hu­man re­pro­duc­tive (germline) cells, this re­search is highly pre­ma­ture,” said the state­ment from the in­ter­na­tional or­ga­ni­za­tion which rep­re­sents more than 200 life-sciences com­pa­nies, re­search in­sti­tu­tions and ad­vo­cacy groups that are fo­cused de­vel­op­ing ther­a­peu­tics, in­clud­ing those in­volv­ing genome edit­ing.

“It is un­ac­cept­able to pur­sue this kind of re­search at this time. We are call­ing for a vol­un­tary world­wide mora­to­rium on this kind of re­search to al­low for rig­or­ous trans­par­ent legal and pol­icy dis­cus­sions and con­tin­ued public de­bate re­gard­ing the science, safety and ethics of mod­i­fy­ing hu­man em­bryos.”

At least four other Chi­nese re­search teams are be­lieved to be pur­su­ing sim­i­lar stud­ies, the Na­ture News re­port said.

When ru­mors be­gan cir­cu­lat­ing ear­lier this month about the im­pend­ing pub­li­ca­tion of the study, some sci­en­tists be­gan call­ing for a halt to the re­search, while oth­ers ar­gued that ba­sic re­search should con­tinue, to see if it may one day help cure cer­tain dis­eases and dis­or­ders.

“Let’s stop that work on hu­man fer­til­ized em­bryos — a very limited as­pect of this — un­til we have had a chance to talk about it,” said Ed­ward Lan­phier, chief ex­ec­u­tive of­fi­cer of Sang­amo Bio­Sciences, in an in­ter­view with AFP.

The In­ter­na­tional So­ci­ety for Stem Cell Re­search also said it is “too soon to ap­ply th­ese tech­nolo­gies to the hu­man germ line, the in­her­ited DNA, in a clin­i­cal set­ting, and any re­search in­volv­ing the use of hu­man em­bryos and re­pro­duc­tive cells should be un­der­taken with care and in ac­cor­dance with strict eth­i­cal guide­lines.”

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