De-extinction – new study provides insights into the limitations of de-extinction across all species

Professor and Director of Center for Evolutionary Hologenomics, GLOBE Institute Tom Gilbert is exploring the possibilities of bringing back the extinct Christmas Island rat through genomic sequencing in a new study, published in Current Biology – However, the hologenomic perspective brings nuance to the core of de-exctinction.

Since becoming a popular concept in the 1990s, de-extinction efforts have focused on grand animals with mythical stature, such as dinosaurs and mammoths, but in a paper published March 9 in the journal Current Biology, a team of paleogeneticists turn their attention to Rattus macleari, and their findings provide insights into the limitations of de-extinction across all species.

De-extinction work is defined by what is unknown. When sequencing the genome of an extinct species, scientists face the challenge of working with degraded DNA, which doesn’t yield all the genetic information required to reconstruct a full genome of the extinct animal. With the Christmas Island rat evolutionary geneticist Tom Gilbert and his colleagues lucked out.

Impossible to create a perfect extinct species

Though the sequencing of the Christmas Island rat was mostly successful, a few key genes were missing. These genes were related to olfaction, meaning that a resurrected Christmas Island Rat would likely be unable to process smells in the way as it would have originally. “With current technology, it may be completely impossible to ever recover the full sequence, and therefore it is impossible to ever generate a perfect replica of the Christmas Island rat,” says Gilbert.

“It is very, very clear that we are never going to be able to get all the information to create a perfect recovered form of an extinct species,” he says. “There will always be some kind of hybrid.”

Though a replica will never be perfect, the key is that scientists are able to edit for the DNA that makes the extinct animal functionally different from the living one.

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