All you need to know about cloning – but were afraid to ask <\/p>
Embryos are made of stem cells that divide to give rise to different types of cells<\/a>, everything from skin to brain cells. <\/strong><\/p> Scientists once thought that reproductive cloning \u2013 creating a genetically identical copy of an individual organism \u2013 would be impossible without using stem cells and that the path leading to mature \u2018differentiated\u2019 cells was irreversible. But clawed frogs proved them wrong…<\/p> In 1958, biologist John Gurdon inserted the nucleus from the mature gut cell of an adult frog into an egg whose nucleus had been removed. This produced tadpoles<\/a> that were clones of the frog that donated the gut cell.<\/p> Gurdon\u2019s experiment showed that mature cells can be reprogrammed to become stem cells. We now know that proteins within an egg cell are what control the genetic instructions in DNA that direct a cell to become a specific type. Reversing that programming let researchers sidestep some ethical issues over using embryonic stem cells, while also paving the way for artificial cloning of complex creatures.<\/p> Dolly<\/a> was the first mammal to be produced by transferring the nucleus from a mature cell into an empty egg. Because the nucleus came from a body or \u2018somatic\u2019 cell from the udder of an adult sheep, the clone was named after buxom country singer Dolly Parton. The lamb, carried to term by a surrogate ewe, was born in 1996.<\/p> Somatic cell nuclear transfer (SCNT) is now the standard technique for cloning. A nucleus is often transplanted into an egg by injection, but Dolly\u2019s creators, Ian Wilmut (pictured) and Keith Campbell, prompted the two cell parts to fuse using an electric pulse. The older way to clone animals is embryo twinning \u2013 splitting an embryo in early development, which is similar to the natural process that forms identical twins.<\/p> Yes… ish. The sequence of DNA letters from an original and replica should be the same. But like twins, those individuals don\u2019t always look identical because the environment can influence which genes are switched on or off, which in turn impacts physical features. <\/p> The first cloned pet, a female calico cat nicknamed CC (for Carbon Copy or Copy Cat), had a coat pattern that was distinct from her \u2018parent\u2019 as genes for coat colour are inactivated at random during development.<\/p> Only about 25 species have been cloned by SCNT, from rats and rabbits to camels<\/a> and coyotes. Individuals have survived to adulthood in 20 or so species. The reason that so few species have been cloned so far is partly because cloning isn\u2019t efficient. <\/p> Horse embryos grown by in vitro<\/em> fertilisation are three times more likely to develop into foals than those cloned in the lab. Based on figures from more than 1,500 domestic dogs that have been created since the first canine was cloned in 2005, cloning efficiency (puppies born after SCNT) is only 2 per cent.<\/p> Dolly died aged six, half the normal life expectancy for a domestic sheep<\/a>. Some people speculated that her death was related to cloning because chromosomes<\/a> have caps called telomeres that protect genes from being lost (the very ends of DNA aren\u2019t replicated when cells divide) and Dolly was cloned from a mature cell with shorter telomeres. But it turns out she was just unlucky and caught a lung disease, and she was euthanised to prevent further suffering. Clones are probably no more likely to die of genetic diseases and their offspring seem healthy, too.<\/p> Many applications aim to benefit humans, such as using cloned pigs as models to study disease, and Dolly\u2019s creators suggested that genetically-engineered sheep could add medicines to milk<\/a>. Cloned livestock hasn\u2019t really taken off, however: of 7 million dairy cattle in the US Department of Agriculture\u2019s database, only 530 cows are clones.<\/p> But cloning can benefit wildlife by boosting a population\u2019s numbers with new individuals cloned from its remaining members. Such \u2018conservation cloning\u2019 has been used to aid endangered species such as North America\u2019s black-footed ferret. Reintroducing extinct species could potentially help restore habitats, too, but of course this involves overcoming challenges beyond cloning.\u00a0<\/p> All you need to know about cloning – but were afraid to ask <\/p>\n","protected":false},"author":24,"featured_media":39708,"template":"","categories":[1],"acf":{"readingTimeMinutes":"4"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold.jpg",1024,683,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold.jpg",800,534,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold.jpg",1024,683,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/44\/2024\/06\/unveiling-the-secrets-of-cloning-how-does-cloning-work-are-clones-exact-copies-and-what-will-the-future-hold.jpg",1024,683,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcwildlife\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"All you need to know about cloning - but were afraid to ask","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/rss_feed\/39707"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/media\/39708"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/media?parent=39707"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcwildlife\/wp-json\/wp\/v2\/categories?post=39707"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}What makes cloning possible?<\/strong><\/h2>
Why was Dolly the sheep so special?<\/strong><\/h2>
How is cloning carried out?<\/strong><\/h2>
Are clones exact copies?<\/strong><\/h2>
Which mammals have been cloned?<\/strong><\/h2>
Are clones healthy?<\/strong><\/h2>
Is cloning actually useful?<\/strong><\/h2>
Could cloning help conservation?<\/h2>
","protected":false},"excerpt":{"rendered":"