Lanzone C, Bidau C J, Giménez M D, Santos J L
Laboratorio de Genética Evolutiva, Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Félix de Azara 1552, (3300) Posadas, Misiones, Argentina.
Genome. 2002 Dec;45(6):1110-5. doi: 10.1139/g02-075.
Synaptic behaviour and the progression of morphological differentiation of the XY chromosome pair during pachytene was studied for the first time in three species of the South American subterranean rodents of the genus Ctenomys (tuco-tucos). In general, synapsis progression in the sex pair could be subdivided into four substages: (i) initial partial synapsis of the X and Y chromosome axes and beginning of the differentiation of the unsynapsed regions; (ii) complete or almost complete synapsis of the Y axis accompanied with morphological differentiation of the unsynapsed region of the X chromosome; (iii) a novel stage exclusive to Ctenomys perrensi consisting in a retraction of the free X axis, associated with the formation of a homogeneous and dense structure along the synaptic region, which leads to the achievement of full synapsis between sex chromosomes; or (iv) an increase in morphological complexity involving extreme splitting of the XY pair. The implications of the peculiar synaptic behaviour displayed by sex chromosomes in C. perrensi, a species complex highly polymorphic for Robertsonian translocations, are discussed in relation to both the triggering of the pachytene checkpoint and the avoidance of non-homologous associations between sex chromosomes and the asynaptic pericentromeric regions of trivalents in translocation heterozygotes.
首次在栉鼠属（tuco-tucos）的三种南美地下啮齿动物中研究了粗线期XY染色体对的突触行为和形态分化进程。一般来说，性染色体对的联会进程可细分为四个亚阶段：（i）X和Y染色体轴的初始部分联会以及未联会区域开始分化；（ii）Y轴完全或几乎完全联会，同时X染色体未联会区域发生形态分化；（iii）一个仅在佩氏栉鼠中出现的新阶段，其特征是游离的X轴回缩，伴随着沿联会区域形成均匀致密的结构，从而实现性染色体之间的完全联会；或（iv）形态复杂性增加，涉及XY对的极端分裂。针对罗伯逊易位高度多态的物种复合体佩氏栉鼠中，性染色体所表现出的特殊突触行为的影响，我们结合粗线期检查点的触发以及避免性染色体与易位杂合子中三价体的非同源着丝粒周围区域之间的非同源关联进行了讨论。
