Harvard geneticist George Church and his colleagues used a gene-editing technique known as CRISPR to insert mammoth genes for small ears, subcutaneous fat, and hair length and color into the DNA of elephant skin cells. The work has not yet been published in a scientific journal, and has yet to be reviewed by peers in the field.
Woolly mammoths (Mammuthus primigenius) have been extinct for millennia, with the last of the species dying out about 3,600 years ago. But scientists say it may be possible to bring these and other species back from the grave, through a process known as de-extinction.
But we won’t be seeing woolly mammoths prancing around anytime soon, “because there is more work to do,” Church told U.K.’s The Times, “But we plan to do so,” Church added.
Not all of the mammoth’s genetic code was spliced into the elephant genome. In fact, only 14 genes were inserted — ones most representative of the hairy, cold-enduring traits of the modern elephant’s ancient relative. The genes were spliced into elephant skins cells using a technique called CRISPR (clustered regularly interspaced short palindromic repeat).
Church and his assistants specifically selected the 14 spliced genes — sourced from the skin cells of a frozen woolly mammoth carcass — for their uniqueness to the woolly mammoth’s hardy appearance.
“We prioritized genes associated with cold resistance including hairiness, ear size, subcutaneous fat and, especially, hemoglobin,” Church told The Sunday Times.
And Church himself has been working on trying to bring back the passenger pigeon, a bird whose flocks once filled the skies of North America but went extinct in the early 20th century. The researchers extracted about 1 billion DNA “letters” from a 100-year-old museum specimen, and are attempting to splice them into the DNA of a common rock pigeon.
The passenger pigeon or wild pigeon (Ectopistes migratorius) is an extinct North American bird. Named after the French word passager for “passing by”, it was once the most abundant bird in North America, and possibly the world. It accounted for more than a quarter of all birds in North America. The species lived in enormous migratory flocks until the early 20th century, when hunting and habitat destruction led to its demise. One flock in 1866 in southern Ontario was described as being 1 mi (1.5 km) wide and 300 mi (500 km) long, took 14 hours to pass, and held in excess of 3.5 billion birds. That number, if accurate, would likely represent a large fraction of the entire population at the time.
Some estimate 3 to 5 billion passenger pigeons were in the United States when Europeans arrived in North America.
Some reduction in numbers occurred from habitat loss when European settlement led to mass deforestation. Next, pigeon meat was commercialized as a cheap food for slaves and the poor in the 19th century, resulting in hunting on a massive and mechanized scale. A slow decline between about 1800 and 1870 was followed by a catastrophic decline between 1870 and 1890. Martha, thought to be the world’s last passenger pigeon, died on September 1, 1914, at the Cincinnati Zoo.
Live passenger pigeon in 1896, kept by C.O. Whitman
SOURCES – Sci-tech, livescience, wikipedia