Wooly Mammoth and Asian Elephants: Genetic Sequencing
Wooly mammoths, with their curly hair and presence in snow and ice, were quite different than current-day Asian elephants. In fact, there was likely a suite of genetic differences between the two, say scientists from Penn State, Nanyang Technological University in Singapore, and the University of Chicago. Their findings were published recently in the journal Cell Reports.
In looking at whole-genome sequences of two wooly mammoths and three modern Asian elephants, the researchers first predicted the function of genetic differences found only in the mammoths, then went a step further than many previous studies, to validate the predicted functions of genes that had been reconstructed in the lab, said a release.
"I've been trying for a long time to show that ancient genomes can be sequenced as accurately as extant genomes, and the woolly mammoth seemed like an ideal species for demonstrating this capability. The Asian elephant genomes were needed for comparison in the subsequent analyses," said Project co-leader Stephen Schuster, formerly of Penn State and now at the Nanyang Technological University in Singapore, according to the Penn State release.
The study worked with the genes of two wooly mammoths that died about 20,000 and 60,000 years ago, respectively, the Penn State release said.
In order to weed out errors, the researchers read each letter in the mammoth's genomic alphabet an average of 20 times, before comparing the sequenced genomes of the three Asian elephants and the more-distantly related African elephant, according to the release.
Amid the intricate reading of letters, the research team found about 33 million places where the nucleotides (the letters) varied among the three species. They found 1.4 million genetic variants in which the two mammoths were the same for one variant and the Asian and African elephants shared a different, likely even more-ancient variant, according to the release.
Among the amino-acid variants shared between the two mammoths but not found in living elephants, the researchers found many changes in genes relating to hair development and how the body stores and processes fats, and how it senses temperature, according to a release.
In other words, the findings showed that wooly mammoths were adapted to endure cold, and even possibly relished it, said Vincent J. Lynch, of the University of Chicago, according to a release.
The researchers would like to see further study of the mammoths and elephants continue in labs, and say that their report shows how to proceed with this, a release said.
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