Chromosome banding and FISH with rDNA probe in the diploid and tetraploid loach Misgurnus anguillicaudatus

Abstract

The chromosomes of diploid and tetraploid loach, Misgurnus anguillicaudatus, were analyzed by staining with Ag, Chromomycin A 3 (CMA 3 )/Distamycin A (DA), and DA/4',6-diamidino-2-phenylindole (DAPI), and fluorescence in situ hybridization (FISH) with 5.8S + 28S rDNA as a probe. Nucleolus organizing regions (NORs) were mapped to the telomeric region of the short arms of the largest (first) metacentric chromosome pair in diploid loach with 2n = 50 and the homologous quartet in tetraploid loach with 4n = 100. The NORs were positive at the same region of the first metacentric chromosome for Ag-and CMA 3 /DA-stainings, but negative for DA/DAPI-staining. Four signals at the homologues within the same quartet suggest the duplication of entire genome from diploid to tetraploid status. However, size difference was detected among rDNA signals by FISH and CMA 3 -banding.

Aneuploid progenies of triploid hybrids between diploid and tetraploid loach Misgurnus anguillicaudatus in China

“…Karyotyping was conducted according to Levan et al (1964). Differential staining with CMA 3 /DA/DAPI (Schweizer 1976;Schweizer et al 1978) and the Ag-NOR method (Howell and Black 1980) was applied to the chromosome slides in accordance with Li et al (2010). FISH using human 5.8S ?…”

“…In China, bisexually reproducing diploid (2n = 50)-tetraploid (4n = 100) complex exists and thus triploid hybrids are easily produced by cross-breeding (Li et al 2008(Li et al , 2010(Li et al , 2011(Li et al , 2012(Li et al , 2013). Since we observed that meiotic cells most frequently exhibited 25IIs and 25Is in triploid hybrids, we predicted the formation of gametes with a mode at 1.5n (37 or 38) chromosomes as a result of equal segregation of 25IIs and random segregation of 25Is (Li et al 2015).…”

Meiotic chromosome configurations in triploid progeny from reciprocal crosses between wild-type diploid and natural tetraploid loach Misgurnus anguillicaudatus in China

“…The fluorochrome CMA 3 (chromomycin A 3 , Wako)/DA (distamycin A, Sigma) staining was also performed to detect NORs according to Li et al (2010Li et al ( , 2011Li et al ( , 2013. FISH with human 5.8S ?…”

“…In Japanese wild populations, no tetraploid loach has been detected (Arai and Fujimoto 2013), but diploid-tetraploid complex exists in Chang Jiang River system in central China (Li et al 2008(Li et al , 2010. Li et al (2012Li et al ( , 2013 verified gonochorisms and sexual reproduction both in Chinese diploid and tetraploid loaches: they reproduce by sexual fertilization of post-meiotic gametes (eggs and spermatozoa) and reciprocal hybridization between diploid and tetraploid produces viable triploid progeny.…”

“…In our study, the pairing behavior of homologous chromosomes (univalent, bivalents or other unusual multivalents) was carefully observed by the use of conventional Giemsa staining, silver staining of nucleolar organizing regions (Ag-NORs), chromomycin A 3 (CMA 3 ) differential staining and fluorescence in situ hybridization (FISH) using a 5.8S ? 28S rDNA probe (Li et al 2010(Li et al , 2011(Li et al , 2013, in order to infer reproductive performance of triploids from the reciprocal crosses between wild-type diploid and natural tetraploid loaches.…”