A new study shows that 87 genes were affected by deletions or short insertions during the evolution of the mammoth. The researchers note that their findings have implications for international efforts to resurrect extinct species, including the woolly mammoth. The study was published today in the journal iScience by researchers at the Stockholm Center for Paleogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History.
One of the most widely discussed methods of resurrecting extinct species is to use genome editing techniques such as Crispr-Cas9 to insert variants of key genes from a species extinct in a genome of her living dad or mum. However, the results of this new study indicate that it may also be necessary to delete certain genes to preserve important biological characteristics while reconstructing extinct genomes.
“Editing the genome from a living species to mimic that of an extinct guardian was never going to be easy, and these new findings certainly illustrate the complexity and challenges ahead,” says Like Dalén, professor of evolutionary genomics at the Center for Paleogenetics.
The researchers behind the study sequenced two new genomes of Siberian mammoths from the last Ice Age and compared them to a total of 33 previously published genomes of mammoths, Asian elephants and African elephants.
The loss of part of a gene , a gene deletion, will affect its function. Similarly, short insertions lead to frameshift mutations that can render genes unreadable. The results show that there are several thousand deletions and short insertions in the mammoth genome, comprising more than three million letters in the genetic code. Overall, the researchers found that most of them did not occur in the genes, indicating that they generally had a negative affect on mammoth viability.
“However, we also found 84 genes that were affected by genomic deletions and three that were affected by short insertions. These structural changes likely had a significant effect on the function of these genes and may have contributed to some of the unique variations. woolly mammoth. “, explains Tom van der Valk, researcher at the Paleogenetics Center.
The change in functionality of these 87 genes may have been vital for mammoths as they developed variations to the cold environment of the Far North. Many adaptive attributes, such as body size and cold tolerance, are regulated by several different genes. Losses of some of these genes may therefore affect the functional pathways that shape the development of these adaptive qualities.
“Several of the genes that were affected are linked to classic woolly mammoth attributes such as hair growth and shape, fat deposition, as well as skeletal morphology and ear shape,” explains Marianne Dehasque, a doctoral student in mammoth genomics at the Centre. for paleogenetics.