Li Shu-Fen, Zhang Guo-Jun, Yuan Jin-Hong, Deng Chuan-Liang, Gao Wu-Jun
College of Life Sciences, Henan Normal University, Xinxiang, 453007, China.
School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, China.
Planta. 2016 May;243(5):1083-95. doi: 10.1007/s00425-016-2485-7. Epub 2016 Feb 26.
The present review discusses the roles of repetitive sequences played in plant sex chromosome evolution, and highlights epigenetic modification as potential mechanism of repetitive sequences involved in sex chromosome evolution. Sex determination in plants is mostly based on sex chromosomes. Classic theory proposes that sex chromosomes evolve from a specific pair of autosomes with emergence of a sex-determining gene(s). Subsequently, the newly formed sex chromosomes stop recombination in a small region around the sex-determining locus, and over time, the non-recombining region expands to almost all parts of the sex chromosomes. Accumulation of repetitive sequences, mostly transposable elements and tandem repeats, is a conspicuous feature of the non-recombining region of the Y chromosome, even in primitive one. Repetitive sequences may play multiple roles in sex chromosome evolution, such as triggering heterochromatization and causing recombination suppression, leading to structural and morphological differentiation of sex chromosomes, and promoting Y chromosome degeneration and X chromosome dosage compensation. In this article, we review the current status of this field, and based on preliminary evidence, we posit that repetitive sequences are involved in sex chromosome evolution probably via epigenetic modification, such as DNA and histone methylation, with small interfering RNAs as the mediator.
本综述讨论了重复序列在植物性染色体进化中所起的作用，并强调表观遗传修饰是重复序列参与性染色体进化的潜在机制。植物的性别决定大多基于性染色体。经典理论认为，性染色体是由一对特定的常染色体随着性别决定基因的出现而进化而来的。随后，新形成的性染色体在性别决定位点周围的一个小区域内停止重组，随着时间的推移，非重组区域扩展到几乎性染色体的所有部分。重复序列的积累，主要是转座元件和串联重复序列，是Y染色体非重组区域的一个显著特征，即使在原始的Y染色体中也是如此。重复序列可能在性染色体进化中发挥多种作用，例如引发异染色质化和导致重组抑制，从而导致性染色体的结构和形态分化，并促进Y染色体退化和X染色体剂量补偿。在本文中，我们综述了该领域的现状，并基于初步证据推测，重复序列可能通过表观遗传修饰（如DNA和组蛋白甲基化）参与性染色体进化，其中小干扰RNA作为介导因子。
