open access

https://hdl.handle.net/2115/51004

The occurrence of hypertetraploid and other unusual polyploid loaches Misgurnus anguillicaudatus among market specimens in Japan

英語

Exotic species

2012-11

Springer

Fisheries science

78(6)

1219-1227

Exotic animals may cause a genetic contamination of indigenous species if they escape and reproduce in wild populations. Loach Misgurnus anguillicaudatus and its related species have been imported to Japan for commercial uses. We collected live loach specimens from central wholesale market in Tokyo. Among 451 specimens, ploidy status was examined by DNA content flow cytometry and polyploid loaches with triploid, tetraploid and other higher DNA content ranges were detected. Hyper-triploid and hyper-tetraploid individuals could be easily detected by flow cytometry using a standard eudiploid, eutriploid and eutetraploid controls and then reproductive capacity of these hyper-polyploid males was examined. Sperm of hyper-triploid males did not exhibit active progressive motility and major populations of spermatozoa or spermatozoon-like cells were detected in triploid and hexaploid ranges. Motile haploid spermatozoa were very few in sperm from hyper-triploid males. Therefore, hyper-triploid males were sterile, whereas hyper-tetraploid males produced fertile hyper-diploid spermatozoa with active progressive motility after contact with ambient water. Viable progeny occurred in the cross between normal wild-type diploid female and hyper-tetraploid males, but androgenotes induced by fertilization of UV-irradiated eggs with sperm of hyper-tetraploid males were inviable hyper-diploid. Cytogenetic analyses in such androgenotes indicated that hyper-tetraploid males should produce hyper-diploid spermatozoa with 2n=54, i.e. presence of four supernumerary micro-chromosomes.

学術雑誌論文

Accepted Manuscript

The final publication is available at www.springerlink.com

0919-9268

1444-2906

AA10993718