Cai Li, Yong Zhang, Jianwen Li, Lesheng Kong, Haofu Hu, Hailin Pan, Luohao Xu, Yuan Deng, Qiye Li, Lijun Jin, Hao Yu, Yan Chen, Binghang Liu, Linfeng Yang, Shiping Liu, Yan Zhang, Yongshan Lang, Jinquan Xia, Weiming He, Qiong Shi, Sankar Subramanian, Craig D. Millar, Stephen Meader, Chris M. Rands, Matthew K. Fujita, Matthew J. Greenwold, Todd A. Castoe, David D. Pollock, Wanjun Gu, Kiwoong Nam, Hans Ellegren, Simon Y. W. Ho, David W. Burt, Chris P. Ponting, Erich D. Jarvis, M. Thomas P. Gilbert, Huanming Yang, Jian Wang, David M. Lambert, Jun Wang, and Guojie Zhang, 'Two Antarctic Penguin Genomes Reveal Insights into Their Evolutionary History and Molecular Changes Related to the Cold Antartic Environment', GigaScience (2014).
Penguins are flightless aquatic birds widely distributed in the Southern Hemisphere. The distinctive morphological and physiological features of penguins allow them to live an aquatic life, and some of them have successfully adapted to the hostile environments in Antarctica. Two of them (Adélie penguin [Pygoscelis adeliae] and emperor penguin [Aptenodytes forsteri]) make the Antarctic continent as their major habitats. To study the phylogenetic and population history of penguins and the molecular basis of their adaptations to the Antarctica, we sequenced the genomes of the two Antarctic dwelling penguin species, Adélie and emperor penguins.
Phylogenetic dating suggests that early penguins arose ~60 million years ago (MYA), coinciding with a period of global warming. Analysis of effective population sizes reveals that the two penguin species experienced population expansions from ~1 MYA to ~100 KYA, but responded differently to the climate cooling of the last glacial period. Comparative genomic analyses with other available avian genomes identified molecular changes in genes related to epidermal structure, phototransduction, lipid metabolism, and forelimb morphology.
Our sequencing and initial analyses of the first two penguin genomes provide insights into the timing of penguin origin, the fluctuations of effective population sizes of the two penguin species over the past 10 million years, and the potential associations between these biological patterns and global climate change. The molecular changes compared to other avian genomes reflect both shared and diverse adaptations of the two penguin species to the Antarctic environment.