摘要
杂种偏分离是指杂交后代群体在某个位点的基因型分离比偏离了预期的孟德尔分离比例的一种现象,是来自不同杂交亲本基因之间的不兼容性所致。功能缺失型和功能获得型的基因间互作都可以导致杂种偏分离,其中前者的机理比较简单,即缺陷型的基因组合导致原有功能丧失而造成细胞死亡。功能获得型杂种偏分离系统是由多基因控制的遗传系统,包含两个基本成分:杀手(killer)因子和护卫(protector)因子,此外还有增强子(enhancer)、抑制基因(repressor)等修饰因子。功能获得型杂种偏分离有通用的遗传模型:具有传递优势的单倍型含有高活性的killer+和protector+;传递劣势的单倍型含有低活性的killer-和protector-;中性的单倍型(广亲和型)则含有killer-和protector+。该系统通过killer和protector间的紧密连锁、修饰因子的积累等途径得以在自然选择中保存下来。尽管不同功能获得型杂种偏分离系统的遗传机理有较高的相似性,但分子机制则大相径庭。文章综述了杂种偏分离的遗传和分子机理以及其与杂种不育的关系,以期为后续杂种偏分离研究提供参考。
Segregation distortion （SD） is defined as abnormal segregation ratio of hybrid offsprings at some genetic loci deviating from the Mendelian ratio. SD results from the incompatibility among genes from different parents, which could be due to loss-of-function or gain-of-function gene interactions. The mechanism for loss-of-function SD is relatively simple： defective gene combination leads to loss of the original function and eventual cell death. The gain-of-function hybrid SD system is a multi-gene genetic system, comprising two basic components： the killer and the protector. Additional modifiers, such as enhancers and repressors, are also involved. There is a general genetic model for gain-of-function hybrid SD： haplotypes with transmission advantage possess high-activity killer＋ and protector＋; those with transmission disadvantage possess low-activity killer- and protector-; neutral haplotypes （wide compatibility types） possess killer- and protector＋. Depending upon close linkage between the killer and the protector and the accumulation of modifiers, the SD system survived through natural selection. Although the genetic mechanismsare highly similar, different gain-of-function hybrid SD systems have distinctive molecular mechanisms. In this re- view, we summarize the genetic and molecular mechanisms of hybrid SD, and the relationship between hybrid SD and hybrid sterility.
出处
《遗传》
CAS
CSCD
北大核心
2015年第2期148-156,共9页
Hereditas（Beijing)
基金
国家自然科学基金项目(编号:31471476)资助
关键词
偏分离
基因互作
广亲和
生殖隔离
杂种不育
segregation distortion
gene interaction
wide compatibility
reproductive isolation
hybrid sterility
作者简介
范智权，硕士研究生，专业方向：遗传学。E-mail：fanzhiquan123@mail．gxu．cn
通讯作者：杨江义，博士，教授，研究方向：植物分子生物学。E-mail：yangjy598@163．com
