title: Multiple sex-chromosome system in a loach fish.
abstract: This study shows an X1X1X2X2/X1X2Y type of multiple sex-chromosome system in the genus Cobitis (Pisces, Ostariophysi). Observation of C-banded male meioses revealed that one arm of the neo-Y always associates end-to-end with one of the X chromosomes. This finding implies that a mechanism might be present that has prevented crossing-over between the ancestral X and Y chromosomes without morphological differentiation. This is the first reported case of multiple sex chromosomes among cyprinoid fish.
authors.affiliation: Department of Fisheries, Faculty of Agriculture, Kyoto University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Saitoh
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D003531:Cypriniformes / Q000235:genetics*; D005260:Female; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D012730:Sex Chromosomes / Q000648:ultrastructure; D012732:Sex Determination Analysis; D014960:X Chromosome / Q000648:ultrastructure; D014998:Y Chromosome / Q000648:ultrastructure