De-extinction

Dolly was born in the mid 1990s and lived normally until the abrupt midlife onset of health complications resembling premature aging, that led to her death.

Because it is possible to sequence and assemble the genome of extinct organisms from highly degraded tissues, this technique enables scientists to pursue de-extinction in a wider array of species, including those for which no well-preserved remains exist.

It had evolved some time in the past from the flighted white-throated rail, but became extinct about 136,000 years ago due to an unknown event that caused sea levels to rise.

However, it has usage as a viable option for de-extinction in cases of functional extinction where all remaining individuals are of the same sex, incapable of naturally reproducing, or suffer from low genetic diversity such as the northern white rhinoceros, Yangtze giant softshell turtle, Hyophorbe amaricaulis, baiji, and vaquita.

[19] The existence of preserved soft tissue remains and DNA from woolly mammoths (Mammuthus primigenius) has led to the idea that the species could be recreated by scientific means.

[27] The team has made changes in the elephant genome with the genes that gave the woolly mammoth its cold-resistant blood, longer hair, and an extra layer of fat.

[27] According to geneticist Hendrik Poinar, a revived woolly mammoth or mammoth-elephant hybrid may find suitable habitat in the tundra and taiga forest ecozones.

[28] George Church has hypothesized the positive effects of bringing back the extinct woolly mammoth would have on the environment, such as the potential for reversing some of the damage caused by global warming.

[29] In an editorial condemning de-extinction, Scientific American pointed out that the technologies involved could have secondary applications, specifically to help species on the verge of extinction regain their genetic diversity.

Scientists captured her, took a tissue sample from her ear, collared her, then released her back into the wild, where she lived until she was found dead in 2000, having been crushed by a fallen tree.

[39] A competing project to recreate the aurochs is the Uruz Project by the True Nature Foundation, which aims to recreate the aurochs by a more efficient breeding strategy using genome editing, in order to decrease the number of generations of breeding needed and the ability to quickly eliminate undesired traits from the population of aurochs-like cattle.

[48] In December 2017, it was announced in the journal Nature Ecology and Evolution that the full nuclear genome of the thylacine had been successfully sequenced, marking the completion of the critical first step toward de-extinction that began in 2008, with the extraction of the DNA samples from the preserved pouch specimen.

[50] Andrew J. Pask from the University of Melbourne has stated that the next step toward de-extinction will be to create a functional genome, which will require extensive research and development, estimating that a full attempt to resurrect the species may be possible as early as 2027.

[49] In August 2022, the University of Melbourne and Colossal Biosciences announced a partnership to accelerate de-extinction of the thylacine via genetic modification of one of its closest living relatives, the fat-tailed dunnart.

[54] The passenger pigeon (Ectopistes migratorius) numbered in the billions before being wiped out due to unsustainable commercial hunting and habitat loss during the early 20th century.

[55] In October 2024, Revive & Restore collaborated with Applied Ecological Institute to simulate forest disturbances in the American state of Wisconsin to see how trees would react to the reintroduced passenger pigeons.

Although scientists were mostly successful in using CRISPR technology to edit the DNA of the living species to match that of the extinct one, a few key genes were missing, which would mean resurrected rats would not be genetically pure replicas.

[69] In late 2022, a group of Russian scientists funded by Sergei Bachin began their project to revive and reintroduce the giant sirenian to its former range in the 18th century to restore its kelp forest ecosystem.

Due to widespread and uncontrollable poaching and civil warfare in their former range, the subspecies' numbers dropped quickly over the course of the late 1900s and early 2000s.

Colossal plans to revive or rediscover the species through genome editing of its closest living relatives, such as the pileated woodpecker and using drones and AI to identify any potential remaining individuals in the wild.

Due to various factors such as habitat loss, wildlife trafficking, trophy hunting, and the Vietnam War, the species population has been reduced to only three male individuals, rendering it functionally extinct similar to the northern white rhinoceros and ivory-billed woodpecker.

Efforts to save the species from extinction through various means of assisted reproduction in captivity have been ongoing since 2009 by the Suzhou Zoo and Turtle Survival Alliance.

[91] Several searches across China and Vietnam are currently underway to locate female individuals to breed with the final known males, or to undergo artificial insemination.

[129] Sallon later challenged her friend, Elaine Solowey of the Center for Sustainable Agriculture at the Arava Institute for Environmental Studies with the task of germinating the seeds.

Solowey managed to revive several of the provided seeds after hydrating them with a common household baby bottle warmer along with average fertiliser and growth hormones.

[133] The Rastreador Brasileiro (Brazilian Tracker) is a large scent hound from Brazil that was bred in the 1950s to hunt jaguars and wild pigs.

It was originally declared extinct and delisted by the Fédération Cynologique Internationale and Confederação Brasileira de Cinofilia in 1973 due to tick-borne diseases and subsequent poisoning from insecticides in attempt to get rid of the ectoparasites.

A deliberate wildfire started by Thomas Chappel, a crew member of the Essex in 1820 is also cited as a reason for the subspecies initial decline.

[143] In 2010, Sarah Sallon of Arava Institute for Environmental Studies grew a seed found in excavations of a cave in the northern Judean desert in 1986.

Despite its status as a delicacy on the east coast of North America, the Montreal melon disappeared from farms and was presumed extinct by the 1920s due to urbanisation in the region and being ill-suited for agribusiness.