SAV­ING NORTH­ERN WHITE RHI­NOS FROM EX­TINC­TION

Pro­tect­ing and res­ur­rect­ing the North­ern white rhino

Vocable (All English) - - Découverte - JOSH GABBATISS

The story of ‘Su­dan’, the last male rhinoceros of his species, has re­ceived a lot of me­dia cov­er­age. Un­for­tu­nately he died last March, and with only two liv­ing fe­males left, the North­ern white rhino, vic­tim of in­ten­sive poach­ing, is very prob­a­bly now ex­tinct… un­less a test tube baby can be bred in the next few years.

IVF-

ready em­bryos have been cre­ated us­ing sperm from north­ern white rhi­nos in an un­prece­dented de­vel­op­ment that paves the way for the res­ur­rec­tion of the species. The sperm was used to fer­tilise eggs from the closely re­lated south­ern va­ri­ety, and the re­sult­ing hy­brid em­bryos have been frozen for im­plan­ta­tion into sur­ro­gate mothers.

2. North­ern white rhi­nos were left func­tion­ally ex­tinct af­ter the last male, Su­dan, passed away in March, but their tragic demise has stim­u­lated ef­forts to de­velop tech­nolo­gies that can bring them back from the dead. Us­ing IVF, the re­searchers hope to see the first north­ern white calf born for decades within the next three years.

DOWN­WARD SPI­RAL

3. The down­ward spi­ral of the rhi­nos caused by poach­ing in cen­tral Africa has been watched help­lessly by sci­en­tists and con­ser­va­tion­ists for years. As numbers dwin­dled and the re­main­ing rhi­nos strug­gled to re­pro­duce, Dr Thomas Hilde­brandt and his team at the Leib­niz In­sti­tute for Zoo and Wildlife Re­search col­lected se­men from the last sur­viv­ing males in the hope it could one day re­vive the north­ern whites.

Their tragic demise has stim­u­lated ef­forts to de­velop tech­nolo­gies.

4. “We came to the point around 2008 that there was no chance to save this sub­species with the tech­niques we had avail­able at that time,” he said. These fears were con­firmed when tests re­vealed the only sur­viv­ing north­ern whites – a mother and daugh­ter named Na­jin and Fatu – had se­ri­ous re­pro­duc­tive prob­lems.

5. That should have been the end, but rapid ad­vances in re­pro­duc­tive and stem cell sci­ence have given Dr Hilde­brandt and his in­ter­na­tional team of ex­perts hope. Us­ing tech­niques nor­mally re­served for the cre­ation of cham­pion race­horses, the sci­en­tists used some of the pre­served sperm to fer­tilise an egg ex­tracted from a south­ern white fe­male. The trial served as a test be­fore ex­per­i­ment­ing with pre­cious eggs taken from north­ern whites. The next step is to gain per­mis­sion from the au­thor­i­ties in Kenya – where Na­jin and Fatu cur­rently re­side – to per­form the same pro­ce­dure us­ing those eggs.

THE FIRST TEST TUBE RHINO EM­BRYOS

6. Hav­ing cre­ated the first ever test tube rhino em­bryos, the sci­en­tists now see a clear path ahead to cre­at­ing a new gen­er­a­tion of north­ern whites us­ing sur­ro­gate mothers in Africa, Europe and the US. “We are quite con­fi­dent with the tech­nol­ogy,” said Dr Hilde­brandt. “We will start with a pure south­ern white rhino em­bryo in the next weeks and months to test the sys­tem, and af­ter that is suc­cess­ful we will im­plant a north­ern white rhino into a sur­ro­gate mother. Our goal is that within three years we have the first north­ern white rhino calf born.”

7. Though there are risks associated with the ex­trac­tion of eggs from adult rhi­nos, not least anaes­thetis­ing a 1,700kg mam­mal, the sci­en­tists are sure north­ern white calves pro­duced this way will be per­fectly healthy. “We make foals from the best cham­pi­ons around the world and they still be­come cham­pi­ons, so the fact the em­bryo is made in the lab­o­ra­tory doesn’t mean it’s a fake em­bryo,” said Pro­fes­sor Ce­sare Galli, a vet­eri­nary medic who led the pro­ce­dures at Avan­tea med­i­cal lab­o­ra­tory in Italy. These ini­tial re­sults were pub­lished in the jour­nal Na­ture Com­mu­ni­ca­tions.

US­ING STEM CELLS

8. In a sep­a­rate ven­ture, the sci­en­tists are aim­ing to pro­duce new sperm and eggs from stem cells, which they hope to cre­ate us­ing sam­ples of skin and other tis­sues col­lected from 12 dif­fer­ent north­ern whites. Though this ap­proach will likely take up to a decade to yield re­sults, the sci­en­tists con­sider it a cru­cial com­po­nent in their long term strat­egy to cre­ate a healthy, ge­net­i­cally di­verse rhino pop­u­la­tion.

9. “The main goal is to have pure north­ern white rhi­nos – it doesn’t mat­ter whether it goes through stem cells or it goes through the har­vest of oocytes [eggs] from the last liv­ing donors,” said Jan Ste­jskal from Dvur Kralove Zoo, which housed the fi­nal north­ern whites be­fore they were moved to Kenya.

10. The sci­en­tists see it as their re­spon­si­bil­ity to bring back the species, which once played a cru­cial role in cen­tral African ecosys­tems, us­ing all the tools at their dis­posal. “The north­ern white rhino didn’t fail in evo­lu­tion, it failed be­cause it was not bul­let­proof,” said Dr Hilde­brandt. “To me if we have a chance to save them I do not un­der­stand why we should not – I do not want to wit­ness north­ern white rhi­nos dis­ap­pear in front of our eyes just be­cause we did not care,” said Mr Ste­jskalf.

(Chine Nou­velle/SIPA)

The world's last two re­main­ing fe­male north­ern white rhi­nos in Ol Pe­jeta Con­ser­vancy in Laikipia county, north­ern Kenya.

(JanSte­jskal/BNPS/SIPA)

A team of ex­perts har­vest­ing eggs from fe­male south­ern white rhi­nos in or­der to fer­tilise them with se­men ex­tracted from Su­dan.

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