Environmental Futures Centre, Griffith University, , Nathan, Australia.
Biol Lett. 2013 Nov 13;9(6):20130748. doi: 10.1098/rsbl.2013.0748. Print 2013.
Penguins are a remarkable group of birds, with the 18 extant species living in diverse climatic zones from the tropics to Antarctica. The timing of the origin of these extant penguins remains controversial. Previous studies based on DNA sequences and fossil records have suggested widely differing times for the origin of the group. This has given rise to widely differing biogeographic narratives about their evolution. To resolve this problem, we sequenced five introns from 11 species representing all genera of living penguins. Using these data and other available DNA sequences, together with the ages of multiple penguin fossils to calibrate the molecular clock, we estimated the age of the most recent common ancestor of extant penguins to be 20.4 Myr (17.0-23.8 Myr). This time is half of the previous estimates based on molecular sequence data. Our results suggest that most of the major groups of extant penguins diverged 11-16 Ma. This overlaps with the sharp decline in Antarctic temperatures that began approximately 12 Ma, suggesting a possible relationship between climate change and penguin evolution.
企鹅是一种非凡的鸟类，现存的 18 个物种生活在从热带到南极洲的各种气候带中。这些现存企鹅的起源时间仍然存在争议。以前基于 DNA 序列和化石记录的研究对该群体的起源时间提出了广泛不同的看法。这导致了对它们进化的广泛不同的生物地理叙述。为了解决这个问题，我们对代表所有现存企鹅属的 11 个物种的 5 个内含子进行了测序。使用这些数据和其他可用的 DNA 序列，以及多个企鹅化石的年龄来校准分子钟，我们估计现存企鹅最近共同祖先的年龄为 20.4 百万年（17.0-23.8 百万年）。这个时间是以前基于分子序列数据估计的一半。我们的研究结果表明，现存企鹅的大多数主要类群在 1100 万至 1600 万年前分化。这与大约 1200 万年前开始的南极温度急剧下降相吻合，这表明气候变化和企鹅进化之间可能存在关系。
