The X1X2Y sex chromosome system in the fish Hoplias malabaricus. I. G-, C- and chromosome replication banding.
Hoplias malabaricus, a widely distributed neotropical fish (Central America to Argentina), may represent a group of distinct species showing diversified cytotypes with respect to chromosome number, morphology and sex systems. One of these karyotypic forms is characterized by an X1X1X2X2/X1X2Y sex chromosome system, with 2n = 40 and 39 chromosomes in females and males respectively. Analyses with G-, C- and chromosome replication banding permitted a better characterization of the sex chromosomes in this cytotype. The Y chromosome, unique in males, resulted from a translocation event between two biarmed chromosomes: one similar to chromosome 6 (X1) and the other one similar to chromosome 20 (X2), the latter corresponding to a probable identification. On the basis of the observed banding patterns, the Y chromosome may represent a stable dicentric, with an inactive centromere interstitially located on its long arm. The results are also related to a specific satellite DNA subfamily, previously characterized in Hoplias malabaricus, which appears to be associated with the X1 chromosome.
Bertollo
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LA
Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil.
Fontes
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MS
Fenocchio
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Cano
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D000782:Aneuploidy; D000818:Animals; D001399:Azure Stains; D001973:Bromodeoxyuridine; D002871:Chromosome Banding; D002875:Chromosomes / Q000235:genetics; D004261:DNA Replication; D005260:Female; D005399:Fishes / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D012730:Sex Chromosomes / Q000235:genetics*
D001399:Azure Stains; D001973:Bromodeoxyuridine