Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, SOKENDAI, Hayama, Japan.
Laboratory of Veterinary Anatomy, Joint Faculty of Veterinary Medicine, Yamaguchi University, Japan.
Genome Biol Evol. 2021 Mar 1;13(3). doi: 10.1093/gbe/evab021.
In rod cells of many nocturnal mammals, heterochromatin localizes to the central region of the nucleus and serves as a lens to send light efficiently to the photoreceptor region. The genus Aotus (owl monkeys) is commonly considered to have undergone a shift from diurnal to nocturnal lifestyle. We recently demonstrated that rod cells of the Aotus species Aotus azarae possess a heterochromatin block at the center of its nucleus. The purpose of the present study was to estimate the time span in which the formation of the heterochromatin block took place. We performed three-dimensional hybridization analysis of the rod cell of another species, Aotus lemurinus. This analysis revealed the presence of a heterochromatin block that consisted of the same DNA components as those in A. azarae. These results indicate that the formation was complete at or before the separation of the two species. Based on the commonly accepted evolutionary history of New World monkeys and specifically of owl monkeys, the time span for the entire formation process was estimated to be 15 Myr at most.
在许多夜间活动的哺乳动物的视杆细胞中，异染色质定位于细胞核的中央区域，充当透镜，将光线有效地传输到感光区域。卷尾猴属（夜猴）通常被认为已经从昼行性转变为夜行性生活方式。我们最近证明，夜猴物种 Aotus azarae 的视杆细胞在其细胞核的中心具有一个异染色质块。本研究的目的是估计形成异染色质块所花费的时间跨度。我们对另一个物种 Aotus lemurinus 的视杆细胞进行了三维杂交分析。该分析显示存在一个异染色质块，由与 A. azarae 相同的 DNA 组成。这些结果表明，在两个物种分离之前或当时，该形成已完全完成。基于新世界猴（特别是夜猴）的普遍公认的进化历史，整个形成过程的时间跨度估计最多为 1500 万年。
