Comparative and evolutionary analysis in natural diploid and tetraploid weather loach Misgurnus anguillicaudatus based on cytochrome b sequence data in central China

Abstract

To obtain the phylogenetic relationship between diploid and tetraploid Misgurnus anguillicaudatus, the mitochondrial cyt b gene in the diploid and tetraploid weather loach were isolated and sequenced.The DNA sequences were analyzed using MEGA 3.0 software to determine the phylogenetic relationship. Forty-five variable sites among cyt b gene sequences and 18 amino acid substitutions occurred within the diploid and tetraploid loaches as deduced from the nucleotide sequences analysis of the cyt b gene. The nucleotide pairwise distance between diploid and tetraploid loach ranged from 0.001 to 0.025. Phylogenetic analysis revealed evolutionary relationships between diploid and tetraploid loach. Our results indicated a significant difference between diploid and tetraploid loach about the cyt b gene. AMOVA analysis indicated that there were no significant genetic variations within diploid loaches (Fst=0.2529, P>0.05) and within tetraploid loaches (Fst=0.0564, P>0.05), neither. However, significant genetic differences were found between diploid and tetraploid loaches (Fst=0.7634, P<0.05). Thus, it is concluded that no reproductive isolation was found within the same cytotypes of different localities, but there was reproductive isolation between these two cytotypes. The diploid loach existed before the tetraploid loach in nature. The present study is the first to describe the phylogenetic relationships of natural polyploidy weather loach using mtDNA cyt b gene.

Untitled

“…Low but overall significant FST value (FST = 0.090, P < 0.001) showed a significant genetic structure for Chinese loach in middle-and-lower reaches of the Yangtze River basin. Based on Cyt b marker, Yang et al (2009) reported no reproductive isolation among different populations in the middle reaches proximity of the Yangtze River basin. It is partially in line with our findings but not a reliable depiction of genetic structure of dojo loach due to drawbacks coherent with Cyt b marker for being single locus and uniparental with low rate of evolution (Birky et al, 1989).…”

“…Genetic variation studies, carried out with allozyme markers on Japanese M. anguillicaudatus showed significant allele frequencies among wild populations (Khan & Arai, 2000). Genetic studies, conducted by Yang et al (2009) using Cyt b marker in the Chinese loach, indicated no reproductive isolation among different loach population. The aforementioned studies cannot be relied upon due to drawbacks associated with biochemical and mitochondrial markers as suggested by Yang et al (2009).…”

“…Genetic studies, conducted by Yang et al (2009) using Cyt b marker in the Chinese loach, indicated no reproductive isolation among different loach population. The aforementioned studies cannot be relied upon due to drawbacks associated with biochemical and mitochondrial markers as suggested by Yang et al (2009). The dwindling populations of Chinese loach in face of damming-induced fragmentation are required to be investigated comprehensively regarding genetic diversity and population configuration using robust and reliable markers.…”

Complete mitochondrial genome of a natural triploid crucian carp mutant, Carassius auratus var. pingxiangnensis, and phylogenetic analysis of different ploidies in crucian carp

“…Yan et al (2009) analyzed the phylogenetic relationship of different polyploid blunt snout bream and concluded that these artificial polyploid hybrids possess the mtDNA of the maternal parent regardless of their ploidy level. In this study, the phylogenetic relationships among branching lineages of ploidy showed that the same ploidy crucian carp did not form a monophyletic lineage; this result was different from that of Yang et al (2009) and was similar to the conclusion of Yan et al (2009).…”

“…Examples of fish groups in which changes in ploidy level have been already identified as key events in their evolution include Acipenseridae (Ludwig et al, 2001), Catostomidae (Ueno et al, 1988), Salmonidae (Crespi and Fulton, 2004), and Cyprinidae (Alves et al, 2001;David et al, 2003). Yang et al (2009) reported the evolutionary relationship between natural diploid and tetraploid weather loach Misgurnus anguillicaudatus and reported that the tetraploid loaches were at the derivative clade, while diploid loaches were at the basal clade of MP and NJ trees. Yan et al (2009) analyzed the phylogenetic relationship of different polyploid blunt snout bream and concluded that these artificial polyploid hybrids possess the mtDNA of the maternal parent regardless of their ploidy level.…”