著者

Ko Tomikawa Norio Kobayashi Hiroshi Morino

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.21, no.1, pp.55-64, 2016-05-25 (Released:2017-02-01)

参考文献数

26

被引用文献数

1

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The taxonomic subdivision of certain Japanese freshwater amphipods into Jesogammarus jesoensis (Schellenberg, 1937), J. hokurikuensis Morino, 1985, J. fujinoi Tomikawa and Morino, 2003, and J. shonaiensis Tomikawa and Morino, 2003 was reassessed using both morphological and molecular data. Putative diagnostic morphological characters did not exhibit consistent geographic distributions, but eight geographically consistent monophyletic clades were detected based on COI and COI+12S rRNA sequence data. Uncorrected COI nucleotide divergences between the clades ranged from 7.0% to 16.4%, a level usually considered to represent inter-specific differences in crustaceans. No morphological features that differentiate the molecular clades were found. While the formal nomenclatural handling of these findings remains a problem for the future, for now we suggest the use of the term “J. jesoensis complex” to represent taxonomic entity consisting of the nominal taxa J. jesoensis, J. fujinoi, J. shonaiensis, and J. hokurikuensis, and potentially a number of hitherto cryptic taxa as well.

著者

Kosuke OTAKA Yuuki HIRADATE Norio KOBAYASHI Yoshiki SHIRAKATA Kentaro TANEMURA

出版者

日本繁殖生物学会

雑誌

Journal of Reproduction and Development (ISSN:09168818)

巻号頁・発行日

pp.2015-013, (Released:2015-06-14)

被引用文献数

3

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During mammalian spermatogenesis, spermatogenic cells undergo mitotic division and are subsequently divided into haploid spermatids by meiotic division, but the dynamics of sex chromosomes during spermatogenesis are unclear in vivo. To gain insight into the distribution of sex chromosomes in the testis, we examined the localization of sex chromosomes before and after meiosis in mouse testis sections. Here, we developed a method of fluorescence in situ hybridization (FISH) using specific probes for the X and Y chromosomes to obtain their positional information in histological testis sections. FISH analysis revealed the sex chromosomal position during spermatogenesis in each stage of seminiferous epithelia and in each spermatogenic cell. In the spermatogonia and leptotene spermatocytes, sex chromosomes were distantly positioned in the cell. In the zygotene and pachytene spermatocytes at prophase I, X and Y chromosomes had a random distribution. After meiosis, the X and Y spermatids were random in every seminiferous epithelium. We also detected aneuploidy of sex chromosomes in spermatogenic cells using our developed FISH analysis. Our results provide further insight into the distribution of sex chromosomes during spermatogenesis, which could help to elucidate a specific difference between X and Y spermatids and sex chromosome-specific behavior.