Study On Morphology And Genetics Of Sebates Koreanus

Sebastes koreanus, which belongs to genus Sebastes, family Scorpaenidae, order Scorpaeniformes, is distributed from coastal water of southwest Korean Peninsula. S. koreanus was discovered and named in 1994 and there is little research about S. koreanustill now. In this study, a new record of S. koreanus from coastal water of China was documented based on morphological characters and DNA barcoding. We analyzed S. koreanuspopulation difference by using morphological analysis and otolith morphological analysis. The result of this study will aid in more explicit species identification within the genus Sebastesin China. This study provides theoretical basis for rational utilization and scientific management of genus Sebastes resources.(A) A new record of S. koreanus from China based on morphological characters and DNAbarcodingA new record of S. koreanus from China is documented based on morphological characters and DNA barcoding.In this study, specimens had the following morphological characteristics:light brown body with dark stripes and tiny dark spots, 4-5 wide indistinct vertical patterns on the side,2 radial stripes behind and below the eyes,1 large dark blotch on the opercle^Additionally, the following meristic characters were recorded:dorsal fin XIV-13, pectoral fin 16, anal fin Ⅲ-6-7, pelvic fin 1-5, lateral line scales 29-30, and vertebrae 26.These findings are consistent with the descriptions of S. hubbsifrom China. The description of S. hubbsi from China is also different from those in Japan and South Koreabut consistent with that of S. koreanus.The COI sequence is recognized as an effective and reliable method for identifying species.Our analysis indicates that S. koreanus specimens in this study can be differentiated from other Sebastes species because the net genetic distance ranged from 3.1% to 7.6%, exceeding the threshold of species delimitation (-2%). By combining the morphological and DNA sequences analyses, it can be concluded that the S. hubbsi from previous studies in China are actually S. koreanus.(B) Morphological analysis of S.koreanus population(1) 17 morphological indices of 51 individuals from 2 populations (Dalian and Qingdao) were measured by conventional morphological and landmark morphological methods and the data was analyzed by using oneway-ANOVA analysis, discriminant analysis, principal componnet analysis and cluster analysis. The results ofone way-ANOVA analysis showed that 9 indices were insignificantly different between Dalian population and Qingdao population; the results of discriminant analysis showed that the correct classification ratio were 100% for both of the two population, scatter diagram of discriminant analysis showed that samples of population Dalian and Qingdao gathered for one group respectively; the results of principal component analysis showed that the first 5 principal components explained 74.067% of morphological difference; the result of cluster analysis showed that population Dalian and Qingdao were pooled in one group respectively. The results of multivariate statistical analysis methods showed that individuals from Dalian population had a great diffenece with Qingdao populations, the reason might be the difference physical and chemical environment of this region and the difference life stage of the two population resulting from the difference sampling time..(2) Otolith morphological characteristics of 43 individuals from 2 populations of Chinese coastal water were analyzed by shape index method and elliptic Fourier method. The results of otolith morphological analysis is difference from morphological analysis. The results of multivariate statistical analysis methods showed that otolith morphology of individuals from Dalian population got little difference with Qingdao populations, the reason might be the gene ralated with S. koreanus’s otolith remained stable during its reproduction and revolution.(C) Characterisation of the mitogenomes of S. koreanusThe complete mitogenomes of S. koreanus were determined, which is a typical circular molecule of 17,606bp in length. The mitogenomes carry set of 22 tRNAs,2 rRNAs,13 protein-coding genes as well as a putative control regionand OL, the gene order of which is identical to those of canonical vertebrate mitogenomes. The nucleotide compositionof the mitogenomes is characterized by a strong excess of C relative to G but a slight excess of A relative to T on the H-strand. Anti-G bias and anti-C bias were found at the third codon positions of H-and L-strand, respectively, ultimately reflected in the codon usage on each strand. The protein-coding genes in all threemitogenomes employed the same start codon ATG except for COI gene being started with GTG. Five stop codons (TAA, TAG, AGG, TA-, and T--) were used in themitogenomes. All tRNA genes could putatively form typical cloverleaf secondary structures with the exception of tRNASer(AGY). In the control region.termination associated sequence domain (TAS)、central conserved domain(CD) and conserved sequence blocks domain (CSB) were recognized.