An international team of scientists has successfully sequenced the nuclear genome of Megaladapis edwardsi, a species of megafaunal lemur that went extinct approximately 1,200 years ago.
Life restoration of the koala lemur Megaladapis edwardsi. Image credit: Michael B. H. / CC BY-SA 3.0.
Megaladapis edwardsi is one of the largest extinct lemurs that once inhabited the island of Madagascar.
Informally known as the koala lemur, it measured over 1.3 m (4.3 feet) in length and had a body weight of 85 kg.
Megaladapis edwardsi was different from any living lemur species: the animal’s body was squat and built like that of the koala; its long arms, fingers, feet, and toes were specialized for grasping trees.
“More than 100 species of lemurs live on Madagascar today, but in recent history, the diversity of these animals was even greater,” said Dr. George Perry, a researcher in the Department of Anthropology, the Department of Biology, and the Huck Institutes of the Life Sciences at the Pennsylvania State University.
“From skeletal remains and radiocarbon dating, we know that at least 17 species of lemurs have gone extinct, and that these extinctions happened relatively recently.”
“What’s fascinating is that all the extinct lemurs were bigger than the ones that survived, and some substantially so.”
To sequence the nuclear genome of Megaladapis edwardsi, Dr. Perry and colleagues extracted DNA from a 1,475-year-old subfossil jawbone.
The unusually well-preserved specimen was uncovered at the site of Beloha Anavoha in extreme southern Madagascar.
“Previous studies based on skull and teeth comparisons suggested that Megaladapis edwardsi was closely related to the living weasel sportive lemur (Lepilemur mustelinus),” said Dr. Stephanie Marciniak, a postdoctoral researcher in the Department of Anthropology at the Pennsylvania State University.
“However, our genetic analyses revealed that the extinct lemur is more closely related to the living red-fronted lemur (Eulemur rufifrons).”
In addition to living lemurs, the researchers compared the genome of Megaladapis edwardsi to the genomes of dozens of more distantly related species, including golden snub-nosed colobine monkeys, which are folivores, and horses, which are herbivores.
“We found similarities between Megaladapis edwardsi and these two species in some of the genes that encode protein products that function in the biodegradation of plant toxins and in nutrient absorption, consistent with dental evidence suggesting that Megaladapis edwardsi was folivorous,” Dr. Marciniak said.
Specifically, the scientists identified similarities between Megaladapis edwardsi and the golden snub-nosed monkey across genes with hydrolase activity functions, and between Megaladapis edwardsi and horse across genes with brush border functions.
“Hydrolases help to break down plant secondary compounds, while brush border microvilli play crucial roles in nutrient absorption and chemical breakdown in the gut,” Dr. Marciniak said.
The results were published in the Proceedings of the National Academy of Sciences.
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Stephanie Marciniak et al. 2021. Evolutionary and phylogenetic insights from a nuclear genome sequence of the extinct, giant, ‘subfossil’ koala lemur Megaladapis edwardsi. PNAS 118 (26): e2022117118; doi: 10.1073/pnas.2022117118
Source link: https://www.sci.news/genetics/megaladapis-edwardsi-genome-09813.html
