Studies On The Morphology And Genetics Of Trachidermus Fasciatus Populations

Roughskin sculpin, Trachidermus fasciatus, which belongs to Scorpaeniformes,Cottidae, is a ClassⅡ of the National Key Protected Wildlife List and in China Red DataBook of Endangered Animals-Pisces. It feeds on zooplankton, fish and shrimp, and has acatadromous life style. Eight geographical groups of T. fasciatus, collected from Dandong,Qinhuangdao, Wendeng, Dalian, Hangzhouwan, Rongcheng, Dongying and Ariake Sea, aredescribed and compared on morphological characteristics and sequence comparison analysisof mtDNA, ISSR, SSR.（1）Fivemeristiccharactersandtwentymorphometriccharactersaremeasuredandthedata are analyzed by one-way ANOVA, discriminant analysis, principle component analysismethod and multivariate analysis method to study the morphological variations among5populations of T. fasciatus. There are no significant differences among the five groups onmorphological characters. As can be seen from the results, there are no significant differencesbetween Dandong and Wendeng geographical groups of T. fasciatus. Although there aresome differences between Daliang and Qinghuangdao geographical groups of T. fasciatus,which are still within the population level.（2）In the present study, the migratory history of Trachidermusfasciatus from Dalian(wild population) and Dongying (one wild population and one cultured population) wasinvestigated using the otolith Sr:Ca ratios by X-ray electron probe microanalyzer (EPMA).Results showed that both estuarine anadromous individuals and estuarine originnon-anadromous ones occurred in the T. fasciatus populations. The result didn’t agree withthe point that this species is only estuarine anadromous. The present is helpful for the fisheriesmanagement. （3）By amplyfing with PCR technique, mitochondrial control region sequences aredetermined from8groups, including Dandong, Qinhuangdao (aquacultured), Wendeng,Dalian, Hangzhouwan, Rongcheng, Dongying and Ariake Sea. Sequence length of thecomplete control region in individuals of T. fasciatus is854bp. There are51polymorphicnucleotide mutation loci in the sequences. The genetic distance between groups of china andgroup of Japan is significant.（4）SequencelengthofthehypervariablecontrolregioninindividualsofT.fasciatusis486bp, including50variable sites, and72haplotypes are found in144individuals. Thehaplotype diversity index of Dandong group is the highest (0.996) while Rongcheng group isthe lowest(0.533). A molecular phylogenetic tree constructed using the neighbor-joining (NJ)method suggested that there are2significant haplotypes in8groups. From the comparison ofthe genetic differentiation index FSTbetween two groups, we can found there is a significantgenetic differentiation between Chinese groups and Japanese groups. The maximum geneticdistance showed between Dandong group and Japanese group (Ariake Sea).（5）Bothmismatchdistributionanalysesandneutralitytestssuggestedalatepopulationexpansion for T. fasciatus population.1141bp sequence which encode the cytochrome bgene of mitochondrial DNA are amplified.31haplotypes are found in47individuals,including38variable sites. Two haplotypes are shared among8groups. The divergence timebetween two lineage (Chinese lineage and Japanese lineage) is410thousand years agoapproximately.（6）Mitochondrial16S rRNA gene is amplified and sequenced,4haplotypes aredetected in11individuals of T. fasciatus. Of the572bp in the16S rRNA gene,3sites arepolymorphic. The average base content are: A=28.8, T=23.9, C=23.8, G=23.5. The resultsshowed that16S rRNA is the most conservative part among the three parts in mtDNA.（7）Inter-Simple Sequence Repeat (ISSR) systems are used to detect the geneticdiversity in T. fasciatus. Eighty-five individuals from three populations are used6ISSR primers screened,22~27clear and reproducible bands are generated. A total of324reproducible loci ranging from0.2to2.5kp were amplified from all the85individuals. TheShannon’s diversity indices are0.3507in wild population (Dandong population) and0.2769in cultured population (Qinhuangdao population). Shannon’s index and the Gst showed thatthe wild stock in Dandong and Wendeng have the highest genetic variation. Apparently theinter-stock’s Gst (0.34900;0.39646) are higher than the wild population (0.07240). And thegene flow between wild populations (Dandong and Wendeng)(6.40608) are higher than thereared groups of Qinhuangdao (0.93266;0.76116), indicating that the genetic differencebetween wild and reared stocks hasn’t reached the population level yet.（8）SimpleSequenceRepeats(SSR)systemsareusedtodetectthegeneticdiversityinT. fasciatus. Fifty individuals from T. fasciatus populations are used8SSR primers screened.As the results showed,8-15alleles on8microsatellite site, which has high PIC and geneticdiversity. There is no significant genetic difference between male and female individuals,which indicate the genetic variation is not only exist in males and females.