Changing environmental conditions and genetic adaptations may explain how penguins radiated and expanded their geographic ranges to encompass diverse environments, a study suggests. Penguins, a family of flightless diving birds, occupy expansive territory across the Southern Hemisphere. However, the drivers of penguin diversification remain unclear. Juliana Vianna, Rauri Bowie, and colleagues analyzed 22 sequenced genomes of 18 living penguin species. The analysis revealed that penguins likely originated during the early Miocene, approximately 21.9 million years ago, along the temperate coastlines of New Zealand and Australia and not in Antarctica, as previously thought. Around 2-9 million years ago, penguins diversified and expanded their range to include colder regions in the Antarctic Peninsula and, subsequently, warmer areas along the South American coast. Penguin diversification and expansion were largely driven by changes in climactic conditions, the opening of the Drake passage, and the intensification of the Antarctic Circumpolar Current. Moreover, the results revealed signals of positive selection for genes involved in cardiovascular activities, such as blood pressure and oxygen metabolism, which are important for diving and regulating body temperature. Such molecular adaptations may have enhanced the ability of some species to dive deeply and enabled penguins to colonize both Antarctica and tropical regions. Together, the findings suggest that changing environmental conditions and genetic adaptations may explain why penguins radiated and expanded their geographic ranges to encompass diverse environments.
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Article #20-06659: "Genome-wide analyses reveal drivers of penguin diversification," by Juliana Vianna et al .
MEDIA CONTACTS: Juliana Vianna, Pontifical Catholic University of Chile, Santiago, CHILE; e-mail: jvianna@uc.cl ; Rauri Bowie, University of California, Berkeley, CA; e-mail: bowie@berkeley.edu
High resolution images, along with caption are credit information can be found at: https://drive.google.com/drive/folders/1wBE4WCnADdzCzTwD6a20yf4axFV2eL7F?usp=sharing
Proceedings of the National Academy of Sciences