Lying under the Siberian midnight sun, this tusk comes from a mammoth – a proboscis of the Ice Age. A new study shows what genetically differentiates these animals from their current relatives.
Not only since “Jurassic Park” did scientists think about whether extinct species could be brought back to life. According to the currently most discussed method, it could work if certain key genes of the no longer existing animals are inserted into the genome of a close relative today. “Modifying the genome of a living species to mimic that of an extinct relative is generally not easy. The new findings highlight the complexity and difficulties ahead,” says Love Dalén from the Center for Paleogenetics in Stockholm.
The mammoth tusk shown in this image has now helped expand knowledge about the genetic make-up of one of these extinct animal species – the woolly mammoth. The tusk discovered in north-eastern Siberia and preserved in the permafrost ice for thousands of years still contained intact DNA. Together with an international team of researchers, Dalén sequenced the genome of this and another Siberian mammoth from the last Ice Age and compared it with the genomes of 33 previously published mammoths and the genomes of Asian and African elephants. The focus was on parts of the gene that are no longer present, so-called gene deletions, and on short insertions, the insertions that can lead to mutations and make the sequence unreadable.
The scientists found that there are many thousands of deletions and insertions throughout the woolly mammoth’s genome, affecting a total of more than three million letters in the genetic code. Most of these mutations occurred outside of the genetic blueprints for proteins. “However, we also found 84 genes affected by genomic deletions and three affected by short insertions,” says Dalén’s colleague and co-author Tom van der Valk. “These structural changes likely had a significant impact on the function of these genes and may have contributed to some of the woolly mammoth’s unique adaptations.”
The changes in these 87 genes could therefore have been decisive for the survival of the animals in the far north. “Several of these affected genes are associated with classic woolly mammoth traits. These include, for example, the fur, the shape of the hair, fat deposits and the shape of the body and ears,” explains co-author Marianne Dehasque. In order to bring about these characteristics in today’s relatives, the scientists would have to cut out entire sections of the genome and insert three genes.