The attempt to genetically rescue extinct and endangered species

Illustration of a female Passenger Pigeon. The species died in captivity in 1914. (PHOTO: Creative Commons)

Passenger pigeons used to be so abundant in the eastern US that its flocks were said to block out the sun. This artwork titled 'Shooting Wild Pigeons in Northern Louisiana' appeared in Illustrated Sporting and Dramatic News, July 3 1875. (PHOTO: Illustrated Sporting and Dramatic News/Wikimedia Commons)

The North American band-tailed pigeon is the closest genetic relative of the passenger pigeon and has been investigated for being used in efforts to revive the extinct species. (PHOTO: Wikimedia Commons / Gregory "Slobirdr" Smith)

A pair of thylacines, aka the Tasmanian tiger, 1902. Efforts are underway to revive the marsupial, which died out in the 1930s. (PHOTO: Wikimedia Commons)

Scientists are working to resurrect the woolly mammoth, which lived during the Pleistocene until its extinction in the Holocene epoch. (PHOTO: Creative Commons / Royal Victoria Museum, Victoria, British Columbia, Canada, 2018)