A study on the distribution of polyploid loaches in China

Abstract

Natural triploid and asexually reproducing clonal diploid loaches are found in Japanese populations of the loach, Misgurnus anguillicaudatus. The distribution of polyploid loaches in Chinese populations has not been studied except for a few cytogenetic studies that described the occurrence of polyploidy. In the present study, we examined the ploidy status of a total of 762 specimens collected from 29 localities in China by measurements of erythrocytic cell nucleus after the ploidy determination performed by chromosome counting and DNA content ‰ow-cytometry in selected individuals. Among diploid, triploid and tetraploid individuals, signiˆcant diŠerences were detected in major and minor diameters of nucleus, and also nuclear volume. A few triploid (3n) loaches were detected in relatively wide areas including Hohhot, Neimenggu (3.3), Tianjin (5.3), Hangzhou, Zhejiang

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

“…Tetraploid karyotype with 100 chromosomes was reported not only in the samples collected from Japanese fish markets and/or farm by Ojima and Takai (1979) and Arai et al (1991a), but also in the samples from Hubei Province, China by Li et al (1983), Yin et al(2005) and Li et al (2008Li et al ( , 2009). Ojima and Takai (1979) arranged 100 chromosomes to 10 M pairs, 4 SM pairs and 36 ST or T pairs, because they supposed that the entire genomes of tetraploid loach might have been already re-diploidized.…”

“…Samples were killed after two injections of phytohemagglutinin (6 µg per g body weight) followed by one injection of colchicines (6 µg per g body weight), and gill tissues were fixed with Carnoy's solution after hypotonic treatment with 0.0375 M KCl according to previous studies (Lin 1982;Zhang 1993;Li et al 2008Li et al , 2009). …”

“…On the other hand, in China, the occurrence of tetraploid M. anguillicaudatus with 100 chromosomes has been reported in samples from Hubei and Guangdong Provinces (Li et al 1983;Li and Li 1987;Yin et al 2005). Recently, Li et al (2008) reported sympatric distribution of diploid and tetraploid individuals in some wild populations in Hubei Province, China, based on chromosome count, nuclear volume of erythrocytes and/or nuclear DNA content flow cytometry.…”

Ploidy manipulation using diploid sperm in the loach,Misgurnus anguillicaudatus: a review

“…This suggests that they presumably have an exotic origin because continental Misgurnus loaches are being imported to Japan as food and tetraploid individuals with 100 chromosomes were reported in the specimens collected from Hubei Province in China (Li et al, 1983;2008).…”

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

“…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).…”