title: Abnormal pairing of X and Y sex chromosomes during meiosis I in interspecific hybrids of Phodopus campbelli and P. sungorus.
abstract: Hybrid sterility plays an important role in the maintenance of species identity and promotion of speciation. Male interspecific hybrids from crosses between Campbell's dwarf hamster (Phodopus campbelli) and the Djungarian hamster (P. sungorus) exhibit sterility with abnormal spermatogenesis. However, the meiotic phenotype of these hybrids has not been well described. In the present work, we observed the accumulation of spermatocytes and apoptosis of spermatocyte-like cells in the testes of hybrids between P. campbelli females and P. sungorus males. In hybrid spermatocytes, a high frequency of asynapsis of X and Y chromosomes during the pachytene-like stage and dissociation of these chromosomes during metaphase I (MI) was observed. No autosomal univalency was observed during pachytene-like and MI stages in the hybrids; however, a low frequency of synapsis between autosomes and X or Y chromosomes, interlocking and partial synapsis between autosomal pairs, and γ-H2AFX staining in autosomal chromatin was observed during the pachytene-like stage. Degenerated MI-like nuclei were frequently observed in the hybrids. Most of the spermatozoa in hybrid epididymides exhibited head malformation. These results indicate that the pairing of X and Y chromosomes is more adversely affected than that of autosomes in Phodopus hybrids.
authors: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
authors: Satoshi
authors: S
authors: Ishishita
authors: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
authors: Kazuma
authors: K
authors: Tsuboi
authors: Laboratory of Animal Cytogenetics, Graduate School of Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
authors: Namiko
authors: N
authors: Ohishi
authors: Applied Biology Co. Ltd., Minato-ku, Tokyo 107-0062, Japan.
authors: Kimiyuki
authors: K
authors: Tsuchiya
authors: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
authors: Yoichi
authors: Y
authors: Matsuda
mesh_terms: D000818:Animals; D056726:Genetic Association Studies; D006657:Histones / Q000378:metabolism; D006824:Hybridization, Genetic; D008297:Male; D008540:Meiosis; D008677:Metaphase; D010641:Phenotype; D017111:Phodopus / Q000235:genetics*; D012670:Seminiferous Epithelium / Q000473:pathology; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology; D013737:Testis / Q000473:pathology; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D006657:Histones