The huge sea cow from the Ice Age was discovered in 1741 by Georg Wilhelm Steller and later called after him. The researchers discovered inactivations of genes in the sea cow genome that are necessary for the typical structure of the outermost layer of the skin. The related sea cows (sirenians) that exist today– dugongs and manatees– are discovered specifically in tropical waters. Of the previous population of Stellers sea cow of around 100,000 animals in the 18th century, just bones can be discovered today on the coasts of Bering Strait islands. Georg Steller first described the sea cow from the Ice Age in 1741.
Today, sea cows are just found in tropical waters. Credit: Colourbox
Giants of the Ice Age: International research group on molecular trail.
The huge sea cow from the Ice Age was found in 1741 by Georg Wilhelm Steller and later on named after him. The 18th-century biologist was interested not just in the huge size of this animal species but also in its unusual, bark-like skin. He described it as “a skin so thick that it is more like the bark of old oaks than the skin of an animal.”
Such a bark-like structure of the epidermis is not found in related sirenians, which today live solely in tropical waters. In scientific circles, it was previously presumed that the bark-like skin was the result of parasite feeding, but likewise insulated heat and thus safeguarded the sea cow well from the cold during the Ice Age and from injuries in the polar seas.
In the existing study, the researchers led by Dr. Diana Le Duc and Professor Torsten Schöneberg from Leipzig University, Professor Michael Hofreiter from the University of Potsdam, and Professor Beth Shapiro from the University of California, reveal that the paleogenomes of Stellers sea cow expose practical modifications. These modifications was accountable for the bark-like skin and the adaptation to cold.
“The most incredible outcome of our examinations is that we have clarified why this giant of the sea had bark-like skin,” stated Diana Le Duc from the Institute of Human Genetics at Leipzig University Hospital. The scientists found inactivations of genes in the sea cow genome that are required for the regular structure of the outermost layer of the epidermis.
” Hereditary problems in these so-called lipoxygenase genes result in what is referred to as ichthyosis in human beings. This is defined by a hardening and thickening of the top layer of skin with large scales, and is in some cases also called fish scale disease,” stated Schöneberg from the Rudolph Schönheimer Institute of Biochemistry. “The outcomes of our research therefore likewise sharpen our view of this scientific picture,” discussed the biochemist, adding: “Here might lie the secret to new therapeutic approaches.”
The scientists identified the hereditary defect by comparing the genome with that of the closest relative, the dugong. The researchers received assistance with their examinations from the Max Planck Institute for Evolutionary Anthropology in Leipzig, which contributed its bioinformatics competence in the analysis of ancient DNA. As an outcome, they identified crucial proof of hereditary changes that may have added to adaptation to the cool North Pacific habitat.
” This is an impressive example of how gene flaws can not only trigger illness, however likewise have benefits depending upon the habitat,” said Hofreiter from the University of Potsdam. The genome information exposed a dramatic reduction in population size. This began 500,000 years prior to the types was discovered and may have added to its termination. Hofreiter summed it up as follows: “With todays molecular genetic explanation, our study closes the circle of an exact observation by a German naturalist in the early 18th century.”
Background
The associated sea cows (sirenians) that exist today– manatees and dugongs– are discovered solely in tropical waters. Of the former population of Stellers sea cow of around 100,000 animals in the 18th century, just bones can be found today on the coasts of Bering Strait islands. Georg Steller initially explained the sea cow from the Ice Age in 1741.
Recommendation: “Genomic basis for skin phenotype and cold adaptation in the extinct Stellers sea cow” by Diana Le Duc, Akhil Velluva, Molly Cassatt-Johnstone, Remi-Andre Olsen, Sina Baleka, Chen-Ching Lin, Johannes R. Lemke, John R. Southon, Alexander Burdin, Ming-Shan Wang, Sonja Grunewald, Wilfried Rosendahl, Ulrich Joger, Sereina Rutschmann, Thomas B. Hildebrandt, Guido Fritsch, James A. Estes, Janet Kelso, Love Dalén, Michael Hofreiter, Beth Shapiro and Torsten Schöneberg, 4 February 2022, Science Advances.DOI: 10.1126/ sciadv.abl6496.