{"id":21434,"date":"2017-09-15T15:28:02","date_gmt":"2017-09-15T22:28:02","guid":{"rendered":"http:\/\/live-hakamagwp.pantheonsite.io\/?post_type=custom_news&p=21434"},"modified":"2017-11-16T15:31:06","modified_gmt":"2017-11-16T23:31:06","slug":"plan-clone-extinct-horse","status":"publish","type":"custom_news","link":"https:\/\/hakaimagazine.com\/news\/plan-clone-extinct-horse\/","title":{"rendered":"The Plan to Clone an Extinct Horse"},"content":{"rendered":"

A horse named Nunki died in a Bahamian forest in July 2015, marking the end of the Abaco Island horse. But thanks to 21st-century technology, the extinction may be temporary. Two years on, Milanne Rehor, head of the Wild Horses of Abaco Preservation Society, has received approval from the Bahamian government<\/a> for an ambitious plan: using Nunki\u2019s DNA and selective breeding to clone the breed back into being.<\/p>\n

How horses came to the Abacos, an archipelago in the Bahamas, remains a mystery, but the herd\u2019s roots can be traced to the steeds brought by Spanish explorers to the Americas 500 years ago.<\/p>\n

In the 1960s, the population was around 200 until a child died while trying to ride one of the horses. The locals responded by killing all but three. When Rehor arrived in 1992\u2014drawn to the islands by a love for the sea and a fascination with the equines\u2014the population had rebounded to an evolutionarily shaky 30 individuals. Although numbers were up, genetic diversity had plummeted, leaving them vulnerable.<\/p>\n

In 1999, Hurricane Floyd drove the horses from the pines to a citrus farm, where a pesticide-riddled diet caused toxins to accumulate in their bodies. No Abaco Island horses were born after 1999. When Nunki died, the breed disappeared.<\/p>\n

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\u201cWhen you get down to the point where there are no more individuals alive of a species, cloning is your only chance,\u201d says Katrin Hinrichs, a veterinary physiologist and pharmacologist at Texas A&M University.<\/p>\n

Cloning extinct animals can work<\/a>, though it comes with limitations. Reviving entire species such as the wooly mammoth<\/a> is still a ways off, and the only successfully resurrected animal\u2014a subspecies of ibex\u2014died within minutes<\/a>.<\/p>\n

But Rehor and the Abaco Island horse have a shot at changing this. Equine cloning has high-profile precedents, such as replicating Gem Twist<\/a>, a gelding and one of showjumping\u2019s greatest athletes. His clones\u2014Gemini<\/a> and Murka\u2019s Gem<\/a>\u2014now pass his champion genetics on to new generations.<\/p>\n

Furthermore, upon Nunki\u2019s death in 2015, Rehor had the foresight to have a veterinarian collect tissue and send the sample to a Texas cloning laboratory, ViaGen. Technicians cultured the cells, then stored them cryogenically.<\/p>\n

Nearly every cell in a living animal contains a complete set of that animal\u2019s chromosomes\u2014all the information needed to re-create the animal in full. In normal fertilization, the oocyte reduces its own chromosomes by half and the sperm provides the second half. When the sperm delivers its share, it triggers the egg to begin the process of becoming an embryo.<\/p>\n

In cloning, you start with a mature, healthy egg from a donor mare. But instead of fertilizing that egg, you remove all of its chromosomes and replace them with the nucleus from the cell of the animal to be cloned\u2014in this case, Nunki.<\/p>\n

\u201cNow you have an egg with two sets of chromosomes, just as if it had been fertilized. You tell it it\u2019s been fertilized, and then it develops into an embryo,\u201d says Hinrichs.<\/p>\n

The embryo\u00a0is cultured for approximately seven days until it can be deemed viable, and is then transferred into a recipient mare. On average, only about 10 percent of clone embryos develop normally. For every three that are successfully transferred, two will result in pregnancy and one in a live foal. The procedure is costly, but ViaGen has offered Rehor US $2-million in pro bono work. Cloning is hardly guaranteed, but it is possible.<\/p>\n

Hinrichs warns, however, that cloning will not save the Abaco Island horse in the long run. It may bring Nunki back, but in order to revive the breed, the cloned mares must reproduce.<\/p>\n

\u201cSo that\u2019s the puzzle. If you have to keep breeding back to non-Abaco horses then, in the end, you\u2019d end up with a non-Abaco horse,\u201d she says.<\/p>\n

\n

Even if it is too late to revive a herd of pure Abaco Island horses, there\u2019s still value in preserving Nunki\u2019s genes.<\/p>\n

Because clones keep genes alive, and cloned horses can be introduced to herds to breed naturally, \u201ccloning offers an amazing opportunity to enhance the gene pool of gene-limited species,\u201d says Hinrichs. Saving Nunki\u2019s genes could one day add outside genetics to a herd facing a bottleneck.<\/p>\n

The precise benefits Abaco genes could confer aren\u2019t known, says Gus Cothran, a veterinarian at Texas A&M University. However, when Cothran compared the Abaco Island horse\u2019s DNA against a database of horse breeds, he found them to be historically significant and genetically unusual. Living on an island, the herd had preserved and amplified its Old World genes in a way that few feral breeds have.<\/p>\n

Thus, Cothran says, saving the genes is worth the effort. \u201cIt\u2019s an insurance policy. You\u2019re trying to keep something that you may need in the future, but you don\u2019t yet know that you need.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

A horse named Nunki died in a Bahamian forest in July 2015, marking the end of the Abaco Island horse. But thanks to 21st-century technology, the extinction may be temporary. Two years on, Milanne Rehor, head of the Wild Horses <\/p>\n

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