XY1Y2 chromosome system in Salinomys delicatus (Rodentia, Cricetidae)

Genetica. 2011 Sep;139(9):1143-7. doi: 10.1007/s10709-011-9616-7. Epub 2011 Nov 22.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arvicolinae / genetics*
  • Chromosome Banding
  • Female
  • Karyotype
  • Male
  • Meiosis
  • Mitosis
  • X Chromosome*
  • Y Chromosome*