中文摘要：

一般认为生命繁衍的过程包括遗传信息的传递和环境因素对优势个体的选择.然而,近年来的一些证据提示,生命体还可主动适应环境因素并发生传代现象,配子以及受精后的表观遗传机制在此过程中扮演的角色虽存争议,但已经逐渐成为生物学研究热点之一.自2009年起,人们认识到精子中存在丰富的表观遗传信息,如DNA和组蛋白修饰,以及小非编码RNA.后续研究进一步发现环境因素,如饮食、压力、化学试剂暴露等,可能通过影响精子表观遗传谱,进而影响后代的表型.由于卵子方面的研究较为有限,本文将主要对精子发生及受精过程中表观遗传信息的调控进行概述,并讨论环境因素通过影响精子表观遗传信息传递给后代的可能机制.

英文摘要：

Epigenetics regulation is generally referred to DNA methylation, histone modification and non-codingRNA, which play important roles in chromatin management and gene expression. Recent studies have found that sperm genome is dynamically regulated by a variety of epigenetics mechanisms. More importantly, emerging evidences suggest that certain epigenetics information could be transmitted from sperm to offspring for limited generations. Here, we have overviewed the epigenetics mechanisms involved in spermatogenesis and after fertilization, and the potential underlining mechanisms of epigenetic inheritance. In the first part, we summarized the current understanding of the regulation of DNA methylation, histone modification and small non-coding RNA in spermatogenesis and early embryonic development. This part started from the establishment of sperm DNA methylome and the reprogramming of paternal DNA methylome after fertilization. We briefly described how DNA methylation is regulated by DNMT and TET proteins, and its role in silencing repetitive elements and imprinting genes. We also summarized the two rounds of reprogramming of DNA methylation after fertilization. During the first round of reprogramming, most DNA methylation signature from germ cells is erased, and somatic DNA methylome is then re-established. The second round occurring from primordial germ cells to germ cells, during which DNA methylation at imprinted genes is erased, and germ cell specific DNA methylome is then re-established. It is generally believed that the two rounds of reprogramming establish the proper DNA methylome for germ cell formation. We then reviewed the specific pattern and functional involvement of sperm histone modifications and histone variants. During sperm maturation, most histones undergo acetylation-mediated degradation and replaced by protamine, resulting in only ~10% genome with retained nucleosomes. The remaining nucleosomes contain canonic histones and various histone variants, including TH2 A, TH2 B, H3 t, H3.3, etc. Import