In new research, scientists analyzed 23 ancient genomes of woolly mammoths (Mammuthus primigenius), including one of the oldest known specimens at 700,000 years old, to identify fixed mutations unique to the species and to obtain estimates of when these mutations evolved. They found that at the time of its origin, the woolly mammoth had already acquired a broad spectrum of positively selected genes, including ones associated with hair and skin development, fat storage and metabolism, and immune system function. They also identified a gene with several mutations that may have been responsible for the woolly mammoth’s miniscule ears.
The evolution of mammoths (genus Mammuthus) was characterized by a series of morphological transitions defined by increasing specialization to life in cold high-latitude environments with open landscapes and grassy vegetation.
This process culminated with the evolution of the woolly mammoth, which originated in northeastern Siberia during the early stages of the Middle Pleistocene, approximately 700,000 years ago, and had become extinct by the onset of the Holocene, 12,000 years ago, across the vast majority of its range.
The woolly mammoth had a Holarctic distribution and inhabited terrestrial environments up to 80 degrees north, even during full glacial conditions.
Compared to both its extant elephant relatives as well as earlier members of Mammuthus, it was uniquely adapted to life in the high Arctic.
The exceptional preservation of woolly mammoth remains recovered from permafrost deposits has enabled scientists to identify a wide range of morphological adaptations, such as thick woolly fur, small ears, short tail, and considerable fat deposits.
Moreover, genetic analyses have hinted at previously unknown physiological adaptations to the Arctic environment, including genes related to thermal sensation and hemoglobin structure.
However, recent work has indicated that only a small subset of these adaptations was unique to the…
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