Ngokokuqala ngqa emlandweni, iqembu lososayensi bezofuzo abavela emazweni ahlukene likwazile ukudala imibungu ye-chimeric esebenza kahle ehlanganisa amaseli kubantu, izingulube nakwezinye izilwane ezincelisayo. Ngokunokwenzeka, lokhu kusivumela ukuthi sithembele eqinisweni lokuthi izitho zabanikeli babantu zizokhulelwa emizimbeni yezilwane.
Lezi zindaba zaziwa kusukela kumagazini weSeli. Ngokusho kukaJuan Belmont, omele iSalka Institute eLa Jolla (eU.SA), ososayensi sebeneminyaka emine besebenza kule nkinga. Lapho umsebenzi usaqala nje, abasebenzi besayensi abaze babone nokuthi unzima umsebenzi abawuthathayo. Kodwa-ke, inhloso ifinyelelwe futhi ingabhekwa njengesinyathelo sokuqala sokulima izitho zomuntu emzimbeni we-porcine.
Manje ososayensi kudingeka baqonde ukuthi bangaguqula kanjani izinto ukuze amangqamuzana omuntu aphenduke izitho ezithile. Uma lokhu kwenziwa, kuzokwazi ukusho ukuthi inkinga yezidalwa ezikhulayo ezifakiwe isixazululiwe.
Amathuba okufaka izitho zezilwane emzimbeni womuntu (i-xenotransplantation) aqala ukuxoxwa cishe emashumini amabili nesigamu edlule. Ukuze lokhu kube yiqiniso, ososayensi kwakudingeka baxazulule inkinga yokwaliwa kwezitho zabanye abantu. Le nkinga ayikaxazululwa kuze kube namuhla, kepha abanye ososayensi bazama ukuthola izindlela ezingenza izitho zezingulube (noma izitho zezinye izilwane ezincelisayo) zingabonakali ekuvikelekeni komuntu. Futhi esikhathini esingaphansi konyaka owodwa nje, isazi sezakhi zofuzo esaziwayo esivela e-United States sakwazi ukusondela ekuxazululeni le nkinga. Ukwenza lokhu, bekufanele asebenzise umhleli we-genomic we-CRISPR / Cas9 ukususa amanye amathegi, okuluhlobo lohlelo lokuthola izinto zangaphandle.
Uhlelo olufanayo lwamukelwa nguBelmont nozakwabo. Kuphela banqume ukukhulisa izitho ngqo emzimbeni wengulube. Ukwakha izitho ezinjalo, amaseli womuntu kufanele angeniswe embungwini wengulube, futhi lokhu kufanele kwenziwe ngesikhathi esithile sokukhula kombungu. Ngakho-ke, ungakha i- "chimera" emele umzimba oqukethe amasethi amabili noma ngaphezulu amaseli ahlukile.
Njengoba ososayensi besho, izivivinyo ezinjalo zenziwe kumagundane isikhathi esithile, futhi ziphumelele. Kepha ukuhlolwa ezilwaneni ezinkulu, ezinjengezinkawu noma izingulube, kwagcina kwehlulekile noma akwenziwa nhlobo. Mayelana nalokhu, uBelmont nozakwabo bakwazi ukwenza inqubekela phambili enkulu kulokhu, njengoba befunde ukwethula noma yimaphi amaseli emibungu yamagundane nezingulube besebenzisa i-CRISPR / Cas9.
Isihleli se-CRISPR / Cas9 DNA siwuhlobo "lombulali" olukwaziyo ngokukhetha ukucekela phansi ingxenye yamaseli ombungu lapho kwakhiwa nje noma yileso sitho. Lapho lokhu kwenzeka, ososayensi bafaka izingqamuzana zeziqu zolunye uhlobo emthonjeni wezakhi zomzimba, okuthe uma sekugcwalise i-niche eshiywe ngumhleli we-DNA, ziqala ukwakha isitho esithile. Ngokuqondene nezinye izitho nezicubu, azithinteki nganoma iyiphi indlela, ezinokubaluleka kokuziphatha.
Ngenkathi le ndlela ivivinywa kumagundane ayekhulile amanyikwe, kwathatha ososayensi iminyaka emine ukuvumelanisa le ndlela nezingulube namaseli womuntu. Ubunzima obukhulu ukuthi umbungu wengulube ukhula ngokushesha okukhulu (cishe kathathu) kunombungu womuntu. Ngakho-ke, uBelmont nethimba lakhe kwadingeka bathole isikhathi esifanele sokufakwa kwamangqamuzana omuntu isikhathi eside.
Lapho le nkinga ixazululwa, izazi zofuzo zathatha indawo yamangqamuzana omzimba wesikhathi esizayo emibungu eyishumi nambili yezingulube, ngemuva kwalokho afakwa komama bokutholwa. Cishe izingxenye ezimbili kwezintathu zemibungu yathuthuka ngempumelelo kungakapheli nenyanga, kepha ngemuva kwalokho ukuhlolwa kwadingeka kumiswe. Isizathu yimithetho yokuziphatha kwezokwelapha njengoba kuchazwe ngumthetho waseMelika.
Njengoba uJuan Belmont ngokwakhe esho, ukuhlolwa kwavula indlela yokulinywa kwezitho zomuntu, ezingafakelwa kabusha ngokuphepha ngaphandle kokwesaba ukuthi umzimba uzozenqaba. Njengamanje, iqembu lezazi zofuzo lisebenza ukulungisa umhleli we-DNA ukuze usebenze emzimbeni wengulube, kanye nokuthola imvume yokwenza lolo vivinyo.
