Several fish species belonging to the family Haemulidae present a karyotype consisting of 48 acrocentric
chromosomes (FN=48), and apparently similar chromosomal microstructure, especially in genus Haemulon,
representing a striking example of intrafamiliar chromosomal conservation. In this study, a more detailed
cytogenetic analysis of the species Conodon nobilis and Pomadasys corvinaeformiswas performed using C-banding,
Ag-NOR, DAPI/CMA3 staining, in situ digestion by distinct endonucleases and double-FISH to map the 18S and 5S
ribosomal genes. Both species showed a similar karyotypic macrostructure with 2n=48 acrocentric
chromosomes and active ribosomal sites at interstitial position on long arms of chromosomal pair 18 and 24
in P. corvinaeformis and C. nobilis, respectively. These sites were the only CMA3
+/DAPI-regions in the karyotype.
Digestion with restriction enzymes revealed a lownumber of digestion sites in the heterochromatic segments of
both species. The data indicate some degree of interspecific evolutionary diversification At the microstructural
level, incorporated in a general pattern of extensive karyotypic conservatism. Thus, the interspecific reproductive
isolation leading to phyletic diversification apparently occurred without the contribution of conspicuous
karyotypic changes.
Several fish species belonging to the family Haemulidae present a karyotype consisting of 48 acrocentric
chromosomes (FN=48), and apparently similar chromosomal microstructure, especially in genus Haemulon,
representing a striking example of intrafamiliar chromosomal conservation. In this study, a more detailed
cytogenetic analysis of the species Conodon nobilis and Pomadasys corvinaeformiswas performed using C-banding,
Ag-NOR, DAPI/CMA3 staining, in situ digestion by distinct endonucleases and double-FISH to map the 18S and 5S
ribosomal genes. Both species showed a similar karyotypic macrostructure with 2n=48 acrocentric
chromosomes and active ribosomal sites at interstitial position on long arms of chromosomal pair 18 and 24
in P. corvinaeformis and C. nobilis, respectively. These sites were the only CMA3
+/DAPI-regions in the karyotype.
Digestion with restriction enzymes revealed a lownumber of digestion sites in the heterochromatic segments of
both species. The data indicate some degree of interspecific evolutionary diversification At the microstructural
level, incorporated in a general pattern of extensive karyotypic conservatism. Thus, the interspecific reproductive
isolation leading to phyletic diversification apparently occurred without the contribution of conspicuous
karyotypic changes.
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