安徽羽叶报春同型花和二型花居群的遗传多样性和遗传结构分析

Analyses on genetic diversity and genetic structure of homostyled and distyled populations of Primula merrilliana

以安徽省秋浦河流域安徽羽叶报春(Primula merrilliana Schltr.)的2个同型花居群[包括铜陵市义安区凤凰山(FHS)和池州市贵池区阴山(YS)居群]和4个二型花居群[包括池州市石台县大王洞(DWD)、池州市贵池区谷村(GC)、池州市石台县立新村(LXC)和池州市石台县莲花田(LHT)居群]为研究对象,采用10对SSR引物对上述6个居群嫩叶的总DNA进行了PCR扩增,在此基础上对各居群遗传多样性和遗传结构进行了分析。结果表明:6个居群的等位基因数、有效等位基因数、稀有等位基因数、观测杂合度和期望杂合度的平均值较低,分别为4.8、2.8、2.7、0.29和0.43,并且,LHT和LXC居群的上述指标较高,而FHS和YS居群的上述指标较低;同型花居群的等位基因数、有效等位基因数、观测杂合度和期望杂合度均低于二型花居群,平均值分别为3.0、2.1、0.12和0.35,且无稀有等位基因。居群间的遗传分化系数和遗传距离均较小,平均值分别为0.34和0.56,且这2个指标与居群间的地理距离无明显相关性。由LHT和LXC居群向其他居群的基因流较大(0.057~0.065),而由FHS和YS居群向其他居群的基因流较小(0.044~0.046);并且,在同型花和二型花居群间存在明显的基因流屏障。分子方差分析(AMOVA)结果表明:同型花和二型花居群间的遗传差异不明显,且64.76%的遗传变异存在于居群内。聚类分析和主坐标分析(PCo A)结果均表明同型花和二型花居群间未明显分组。研究结果显示:安徽羽叶报春居群的遗传多样性较低;同型花居群的遗传多样性低于二型花居群,但二者的遗传分化并不明显。建议加强对秋浦河流域上游安徽羽叶报春居群及其生境的保护,并将同型花居群视为不同于二型花居群的独立单元进行遗传保护。

Taking two homostyled populations [including populations from Fenghuangshan in Yian District of Tongling City（ FHS） and Yinshan in Guichi District of Chizhou City（ YS） ]and four distyled populations [including populations from Dawangdong in Shitai County of Chizhou City（ DWD）,Gucun in Guichi District of Chizhou City（ GC）,Lixincun in Shitai County of Chizhou City（ LXC）,and Lianhuatian in Shitai County of Chizhou City（ LHT） ]of Primula merrilliana Schltr. in Qiupu River basin of Anhui Province as research objects,PCR amplifications of total DNA from tender leaves of above six populations were conducted by using ten pairs of SSR primers. On the basis,genetic diversity and genetic structure of each population were analyzed. The results show that averages of allele number,effective allele number, rare allele number, observed heterozygosity, and expected heterozygosity of six populations are relatively low with values of 4. 8,2. 8,2. 7,0. 29,and 0. 43,respectively,and above indexes of LHT and LXC populations are relatively high,while those of FHS and YS populations are relatively low; allele number, effective allele number, observed heterozygosity, and expected heterozygosity of homostyled populations are all lower than those of distyled populations with averages of3. 0,2. 1,0. 12,and 0. 35,respectively,and without rare allele. Genetic differentiation coefficient and genetic distance among populations are both relatively small with averages of 0. 34 and 0. 56,respectively,and these two indexes have no obvious correlation with geographic distance among populations. Gene flows from LHT and LXC populations to other populations are relatively large（ 0. 057-0. 065）,while those from FHS and YS populations to other populations are relatively small（ 0. 044-0. 046）. Moreover,there are obvious gene flow barriers between homostyled and distyled populations.The result of analysis of molecular variance（ AMOVA） shows that the genetic difference between homostyled and distyled populations is not obvious,and 64. 76% of the genetic variation is existed within population. The cluster analysis and principal coordinate analysis（ PCo A） results both show that there is no obvious group between homostyled and distyled populations. It is suggested that the genetic diversity of P. merrilliana populations is relatively low; that of homostyled populations is lower than that of distyled populations,but the genetic differentiation between them is not obvious. It is recommended to strengthen the protection of P. merrilliana populations and their habitats in upper reaches of Qiupu River basin,and homostyled populations should be considered as independent units differing from distyled populations for genetic protection.