Where things get a little hairy: resurrecting the mammoth

In a review published earlier this month, UC Santa Cruz professor Beth Shapiro summarises present understanding of the possibility for "resurrecting" extinct species---that is, "de-extinction," and how and why it could become reality. Shapiro describes this process not so much about bringing back extinct species, but rather about re-introducing extinct traits via genome editing. As extinct taxa are recovered with ancient DNA available for analysis, the prospect of editing a closely related extant genome to possess autapomorphic sequences of the extinct species becomes possible; George Church's lab at Harvard University has already done this by replacing 14 loci in elephant cell lines with their mammoth-specific counterparts. If this could be done genome-wide, and a viable trans-nuclear embryo established in a host mother, a mammoth could hypothetically be "cloned" in much the same way as Dolly the Sheep.

Fig. 1 - Woolly mammoths as portrayed by the acclaimed Charles R. Knight

Even this would fall short of properly "resurrecting" the mammoth, however, because this synthetic creation would fundamentally develop and live in a different environment, in different social groups, with different stimuli and an ecological niche distinct from its prehistoric forebears'; changes genetic and epigenetic resultant from inconsistencies with the extinct mammoth's Pleistocene habitat would give rise to an animal likely different from the original (and unknowably so). Shapiro notes all this in accessible and fascinating detail, and describes de-extinction as more likely the use of genome editing to resurrect specific phenotypes---instead of a mammoth, a cold-adapted hairy elephant; instead of an aurochs, a large lean cattle with fewer maladaptive vestiges of artificial selection; instead of a Neanderthal, human cell lines with Neanderthal-derived genes relevant to health or disease. The entire prospect is fascinating and blurs the line between science-fiction and science (the animated sequence from the first Jurassic Park comes to mind), and raises riveting prospects and points of debate for the generations of scientists to come.

Fig. 2 - Remember me?

Source article published in Genome Biology Nov 2015