Mitochondrial genome characteristics and phylogenetic analysis of Pseudogastromyzon
Pseudogastromyzon,a benthic primary freshwater fish distributed in the foothills of the southeast coast of China,is a fine material to study the origin,distribution pattern and formation process of freshwater fish in this area.Since the establishment of the genus,its taxonomic research has attracted much attention,because it is the basis for studies of population genetics,systematic evolution and biogeography.Previous studies mainly focused on morphology,but there was little difference in body surface markings and body proportions used for identification among different species.With the accumulation of the number of specimens,the degree of overlapping of identification features among species increased,and many new problems arised.In view of the above reasons,coupled with the difficulty of specimen collection,there has been no complete report on the phylogeny of the genus.In recent decades,molecular biological techniques have been applied in fish classification.Mitochondrial genes are widely used due to their simple molecular structure,strict maternal inheritance and rapid evolution.In this paper,samples of all eleven species of the genus Pseudogastromyzon in China were collected,and mitochondrial genome sequences of each species were determined.Based on the systematic analysis and comparison of mitochondrial genomes,phylogenetic relationship of the genus was reconstructed by using mitochondrial genomes as molecular markers,and the validity of some species was determined in combination with previous morphological studies.The results showed that:lengths of mitochondrial genomes of Pseudogastromyzon were from 16 560 bp to 16 574 bp,and the gene composition and arrangement pattern was basically consistent with mitochondrial genomes of most vertebrates;A+T content of mitochondrial genome sequences all exceeded 50％,and there was anti-G bias.By comparing the sequences of 13 protein-coding genes and control region of mitochondrial genomes from eleven species of Pseudogastromyzon,a 6-bp base insertion and deletion was found in CO Ⅰ gene.The evolution rate of D-loop was among the protein-coding genes,and ND4,ND5,Cyt b and D-loop genes were suitable as molecular markers for studying the phylogeny of this genus.According to the interspecies genetic distance of the eleven species based on CO Ⅰ gene sequences and phylogenetic tree of Pseudogastromyzon constructed by mitochondrial genome sequences,the results showed that P.fasciatus jiulongjiangensis and P.meihuashanensis were synonym of P.fasciatus fasciatus.The nine effective species could be divided into two major classes:three species whose chin adhesive apparatus were club-shaped clustered into one class;the remaining six whose chin adhesive apparatus were wave-shaped clustered into the other class.
Pseudogastromyzonmitochondrial genomegenetic characteristicsdetermination of valid speciesphylogeny
万方数据
维普
