Colossal Biosciences Brings Back the Dire Wolf: Inside the De-Extinction of Romulus, Remus, and Khaleesi

Romulus, Remus, and Khaleesi were born via surrogate dogs at a 2,000-acre preserve, produced through 20 gene edits in gray wolf DNA, alongside a novel cloning method and four cloned red wolves using recovered ghost alleles.

Three dire wolf pups have been born. Romulus, Remus, and Khaleesi arrived via surrogate dogs at a 2,000-acre ecological preserve, produced using genetic information recovered from a 13,000-year-old tooth and a 72,000-year-old ear bone, through 20 edits in 14 gray wolf genes; at six months, Romulus and Remus weighed 80 pounds and measured 4 feet long, on track for a potential 6 feet and 150 pounds.

The cloning method broke new ground. Rather than extracting tissue biopsies, Colossal isolated endothelial progenitor cells from blood, a less invasive process that co-founder George Church described as a game changer for cloning efficiency. Alongside the dire wolf work, four red wolves were cloned using ghost alleles recovered from populations along the Texas and Louisiana coast. The effort aims to restore lost genetic diversity to one of North America’s most critically endangered wolf species.

This story is based on original reporting by Jeffrey Kluger for TIME. Read the full feature on TIME → https://time.com/7274542/colossal-dire-wolf/