基于D-Loop序列的罗非鱼选育群体遗传变异分析

Analysis of genetic diversity of tilapia during selection processing based on D-loop sequence

摘要:

对吉富品系尼罗罗非鱼（Oreochromis niloticus）不同世代选育群体D-loop序列进行测定和分析，47个样本经重排比较后获得902 bp的同源序列。共检测到225个变异位点，占分析位点数的24.94%。同源序列中多态位点比例随着选育世代数的累进，呈现出降低的趋势。核苷酸多样性指数也呈现出同样的降低趋势，F₀、F₆、F₇、F₈、F₉分别为0.074 02、0.068 72、0.064 15、0.049 52、0.044 55。多态位点比例、核苷酸多样性指数在不同世代间的变化趋势一致表明，随选育的进展，选育群体逐步纯化。选育基础群体F₀与F₆、F₇、F₈、F₉之间的遗传距离呈增大趋势，表明较短时间内的人为选择可以造成与长期地理隔离效应相当的群体遗传分化。

Abstract:

The mtDNA control region of GIFT strain Oreochromis niloticus in F₀, F_6-9 generation were amplified and sequenced. 225 loci were polymorphic and accounted for 24.94% in 902 base pairs of 47 samples. The ratio of polymorphic loci was highest in F₀, and decreased with selection proccessing. Nucleotide diversity index were 0.074 02, 0.068 72, 0.064 15, 0.049 52, 0.044 55 for F₀, F₆, F₇, F₈, F₉, respectively. The ratio of polymorphic loci, nucleotide diversity index among these five generations showed that the selected populations were getting purer after selection procession. Genetic distances between F₀ and these four selected populations were increased with selection procession, which suggested that selection could result in genetic differentiation just as caused by longterm geographical isolation.