The most comprehensive study ever done on the woolly mammoth genome is shedding light on how genetic variants affect a wide range of traits that helped these now-extinct creatures to adapt to the frigid conditions of the last glacial period.
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After analyzing the genetic material, the experts also found that some segments of the genome were responsible for the animal’s distinctive head shape, their short tails and small ears.
Modifying Asian elephants with mammoth genes could help the modern-day subtropical creatures live in colder locales, “possibly extending the geographical range of an existing endangered species northward to areas at much lower risk of conflict with humans”, Church said.
“We wanted to identify the genetic changes that happened in woolly mammoths that make them mammoth-like”, explains Lynch. One mammoth died about 20,000 years ago, and the other died 60,000 years ago. Therefore, it was the proteins that dictated the different lipid metabolism of the woolly mammoth, their circadian rhythm, as well as the development of hair and skin.
He and some colleagues recently compared the DNA of woolly mammoths to DNA of the modern Asian elephant, which dwells in warm tropical forests and is their closest living relative.
“They are an excellent model to understand how morphological evolution works, because mammoths are so closely related to living elephants, which have none of the traits they had”, he added. Of these “shared, derived” variants, the scientists identified 2,020 that resulted in a change to the amino-acid sequence of a protein encoded by a gene and 26 that caused the loss of a gene’s function.
The scientists found that a certain protein, known as TRPV3, which is responsible for body fat storage, body hair and perceiving temperatures, was mutated in wooly mammoths.
The research scientists “resurrected” the gene of vast known as TRPV3. When scientists injected TRPV3 into human cells, the cells produced a protein less responsive to heat. This result is supported by observations in mice that have TRPV3 artificially silenced. These mice prefer colder environments than normal mice and have wavier hair.
Lynch says their genome-wide analysis can’t say with absolute certainty how each of these mammoth genes affected them physically, but effects can be inferred through lab tests.
Lynch realizes that the high-quality sequencing and analysis of woolly mammoth genomes can serve as a functional blueprint for efforts to “de-extinct” the mammoth.
“It won’t be that long till we’re technically able to do it, but whether we should is a different question”, said study co-author Vincent Lynch, an evolutionary biologist at the University of Chicago.
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The first draft genome contains the catalog of more than 3 billion DNA bases that make up the mammoth’s genetic blue print. This study could also help lead to bringing back the extinct animals. Additional authors include Webb Miller (project co-leader), Oscar Bedoya-Reina, Aakrosh Ratan, Daniella I. Perry at the Penn State Departments of Anthropology and Biology; and Michael Sulak at the Department of Human Genetics at the University of Chicago.
