INVESTIGADORES
GIMENEZ mabel dionisia
artículos
Título:
Synaptic behaviour and morphological modifications of the X and Y chromosomes during pachytene in three species of Ctenomys (Rodentia, Caviomorpha, Ctenomyidae)
Autor/es:
C. LANZONE; C.J. BIDAU; M.D. GIM√ČNEZ; J.L. SANTOS
Revista:
GENOME
Editorial:
NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS
Referencias:
Lugar: Otawa; Año: 2002 vol. 45 p. 1110 - 1115
ISSN:
0831-2796
Resumen:
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.