着丝粒横裂和着丝粒并合及其在高等植物染色体进化中的意义

本文讨论了着丝粒横裂和并合及其在高等植物染色体进化中的意义。着丝粒横裂和着丝粒并合是两个矛盾又辩证统一的过程,是染色体的基本变异形式之一,它们同时影响着植物类群的染色体基数、核型对称性、连锁关系、交叉频率和位点等细胞遗传学的重要方面.从而在高等植物染色体进化中起着重要作用,着丝粒和端粒的复制模型为着丝粒的横裂与并合提供了可能的机理,但尚待直接的生物化学证据的证实,原始基数的确定是判别着丝粒横裂与并合的关键。

CENTRIC FISSION, CENTRIC FUSION AND THEIR SIGNIFICANCE IN CHROMOSOMAL EVOLUTION OF AlGHER PLANTS

In this paper, centric fission, centric fusion, their mechanism and significance in chromosomal evolution of higher plants were reviewed. Centric fission and centric fusion were two contradictive and dialectally unified processes. They were fundamental types of chromosomal variations of higher plants, both influencing on basic number, symmetry & asymmetry of karyotype, linkage relationship, frequency and locus of crossing over etc. of plant taza. Hence they have significant roles in chromosomal evolution. The models for centromere and telomere duplication give us hints to understand the mechanism of centric fission and fusion, but it is still awaiting to be confirmed by biochemical evidences. Ancestral basic number is a key to determine whether a variation is fission or fusion.