title: XY1Y2 chromosome system in Salinomys delicatus (Rodentia, Cricetidae).
abstract: Salinomys delicatus is considered a rare species due to its restricted and patchy distribution, poor records and low abundances. It is also the phyllotine with the lowest known diploid chromosome number (2n = 18), however its sex chromosome system has never been described. Here, we studied the chromosomes of six females and three males with bands G, C, DAPI/CMA(3) and meiosis. In males, the chromosome number was 2n = 19, with one large metacentric X-chromosome and two medium-sized acrocentrics absent in females. The karyotype of females was the same as previously described (2n = 18, FN = 32), with X-chromosomes being metacentric and the largest elements of the complement. In males, the two acrocentrics and the large metacentric form a trivalent in meiotic prophase. This indicates that S. delicatus has XY(1)Y(2) sex chromosomes, which is confirmed by G and DAPI bands. Constitutive heterochromatin (CH) is restricted to small pericentromeric blocks in all chromosomes. The X-chromosome shows the largest block of centromeric CH, which could favor the establishment of this X-autosome translocation. This sex chromosome system is rare in mammals and, compared with other phyllotine rodents, S. delicatus seems to have undergone a major chromosome restructuring during its karyotypic evolution.
authors: Grupo de Investigaciones de la Biodiversidad, IADIZA, CONICET, CCT-Mendoza, CC 507, CP5500 Mendoza, Argentina. celanzone@mendoza-conicet.gob.ar
authors: C
authors: C
authors: Lanzone
authors: D
authors: D
authors: Rodríguez
authors: P
authors: P
authors: Cuello
authors: S
authors: S
authors: Albanese
authors: A
authors: A
authors: Ojeda
authors: V
authors: V
authors: Chillo
authors: D A
authors: DA
authors: Martí
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000235:genetics*; D002871:Chromosome Banding; D005260:Female; D059785:Karyotype; D008297:Male; D008540:Meiosis; D008938:Mitosis; D014960:X Chromosome; D014998:Y Chromosome