贵州两地理群体鲫的系统发育及遗传分化

分布于贵州省普安县青山镇和威宁县草海的鲫,系喀斯特山区彼此隔离的2个地理群体,为探明其遗传结构,探讨彼此间系统关系及遗传分化情况,本研究对其mt DNA D-loop区进行测序分析。结果显示:普安鲫有919和921~927bp 8种序列长度类型,分属27种基因型和14种单倍型;草海鲫有923~925bp 3种序列类型,分属11种基因型和6种单倍型;序列差异因碱基替换和缺失/插入不同所致。普安鲫是银鲫和鲫指名亚种及其所含3个亚类群的混生群体;草海鲫为鲫指名亚种2个亚类群的混合群体。普安鲫及其指名亚种群体遗传多样性水平中等,草海鲫及其指名亚种群体遗传多样性偏低,普安的银鲫群体遗传多样性水平极低。研究表明,喀斯特山区2地理群体鲫具有群体组成复杂和母系来源多样的发育特点,因长期的地理隔离、生殖隔离和基因交流缺乏所造成的遗传漂变和进化速率差异,其基因型和单倍型呈明显地理分布格局,各群体间遗传分化严重。普安的银鲫系东北银鲫起源,遗传变异低,急需改善亲本质量。草海鲫因奠基者效应、瓶颈效应和遗传漂变导致其遗传多样性偏低。本研究丰富了喀斯特山区鱼类群体遗传学资料,为地方鲫种质资源鉴定与评价提供基础资料。

Phylogenetic relationship and genetic differentiation of two geographical populations of Carassius auratus in Guizhou Province

Puan Carassius auratus and Caohai Carassius auratus were the special isolated groups of crucian carp in karst mountain areas, in order to fully understand the genetic structure systematically, and discuss the phylogenetic relationship and genetic differentiation each other, in this study, the mitochondrial DNA control region of two geographical populations was analyzed by the sequencing technology. The results showed that Puan C.auratus had eight types of sequence length of 919 bp and 921-927 bp, belonging to 27 kinds of genotypes and 14 kinds of haplotypes; Caohai C.auratus had three sequence types of 923/924/925 bp, belonging to 11 kinds of genotypes and 6 kinds of haplotypes; The sequence variation due to the differences of nucleotide substitution and the deletion/insertion. The molecular cluster confirmed that Puan C.auratus was the mixed groups of C.a.gibelio and C.a.auratus including their 3 sublineages. Caohai C.auratus was the mixed groups of 2 sublineages of C.a.auratus. The genetic diversity of the mixed groups of Puan C.auratus containing C.a.auratus was the medium level, and that of Caohai C.auratus was lower, while the genetic diversity level of Puan silver carp was extremely low. The study indicated that the two geographical populations of crucian carp in Karst Mountain had a characteristic of complicated group composition and diversity sources of matrilineal. As the long-term geographical isolation, reproductive isolation and lack of gene flow resulted in the difference of genetic drift and evolutionary rate, which made the genotype and haplotype of D-loop also had obvious geographical distribution pattern, the genetic differentiation was serious among various groups. Puan silver carp and silver carp in northeast of China belong to the same origin of matrilineal line, the degree of population genetic variation was so low that improving the quality of the parents was in urgent need. The founder effect, the bottleneck effect and genetic drift lead to the low genetic diversity current situation of Caohai C.auratus. This experiment enriched the fish population genetics research materials in the Karst Mountain, in order to provide basic data of the germplasm resources appraisal and evaluation of the local crucian carp.