Artículo de revista
Genomic compatibility between two phyllotine rodent species evaluated through their hybrids
Fecha
1999Registro en:
Hereditas, Nº 131, 1999. pp. 227-238
DOI: 10.1111/j.1601-5223.1999.00227.x
Autor
Walker Bozzo, Laura
Rojas, Mariana
Flores Carrasco, Sergio
Spotorno Oyarzún, Ángel
Manríquez Soto, Germán Raúl
Institución
Resumen
In order to investigate the genomic compatibility between allopatric rodent species, Phyllotis durivini and Pliyllotis
mugister, we have studied several cytogenetic and reproductive features of their laboratory hybrids. Of thirty-one pairings
between species, only five were successful, producing eleven newborns. Like parents, hybrids had 38 metacentric
chromosomes, except for the subtelocentric Y chromosome inherited from P. mugisteu. There was almost total C and G
band correspondence between homeologous autosomes. However, parental sex chromosomes had different morphology,
C and G bands. Ag-NOR bands appeared as small telomeric Ag+ regions, distributed in four chromosomal pairs of
durwini, three of mugister and four homeologous chromosomes of the hybrids. The three forms had similar indexes of
NOR activity per cell, in spite of the variability in NOR expression which was always detected. Usually, only one member
of parental homologous chromosomes showed AgNOR + ; nevertheless, both homeologous chromosomes were active in
many hybrid cells. The frequencies of cells that expressed their ribosomal genes in the two homologous or homeologous
NOR chromosomes were similar in parental and hybrid cells. These results strongly suggest that ribosomal genes of both
parental genomes would function codominantly in the hybrids. The gonad histological and morphometric analyses
showed that hybrids conformed to Haldane's rule, since females were fertile and males were infertile. Our results indicate
that P. durwini and P. mugister genomes can function in relative harmony and compatibility when they are placed together
in their laboratory generated hybrids, suggesting that these species have few genetic differences, probably because they
have recently diverged.