摘要
利用RAPD分子标记,对锡林郭勒草原主要建群种大针茅(StipagrandisP.Smirn.)5个种群共90个基因株的遗传多样性进行了分析。由16个10碱基随机引物共扩增得到310条清晰可重复的RAPD片段,且全部为多态性条带。利用POPGENE软件对RAPD数据进行分析可以看出,不同地理种群大针茅存在很高的遗传变异,且大部分变异存在于种群之内,只有少量变异存在于种群之间(≈28%)。Pearson相关分析表明,大针茅种群内基因多样性与温度因子(≥10℃年积温、年均温和1月份均温)之间存在显著(p<0·05)或极显著(p<0·01)的相关关系;Mantel检验结果显示,大针茅种群间的遗传距离与种群间的实际地理距离之间不存在显著的相关关系(r=0·184,p=0·261),但与水热因子的分异之间存在显著(p<0·05)或极显著(p<0·01)的相关关系。这些都表明水热差异的自然选择引起大针茅种群RAPD标记的生态地理分化,而迁移和遗传漂变对大针茅种群间的分化不起决定作用。
Stipa grandis steppe, a tussock steppe in the Mid-Asian grassland of Euro-Asian Steppe Region, is one of the representative formations of the typical steppes in Inner Mongolia, China. Increasing awareness of diversity reduction has brought about the increased interest in the studies of dominant species like S. grandis, both at home and abroad. A study on genetic diversity and genetic structure of the dominant species will provide a better measure of the ecosystem＇ s genetic health, as well as provide a scientific basis for its conservation and utilization. However, there have only been a few studies on S. grandis genetic diversity so far and studies on the association with ecological factors are even rare. Therefore, it is necessary to thoroughly investigate the genetic characters of S. grandis. In the present study, genetic diversity in random amplified polymorphic DNAs （RAPD） was studied for 90 genets of the S. grandis, from 5 natural populations sampled in Xilingol steppe. Sixteen oligonucleotides screened from 100 random decamer primers were used to amplify 310 scorable RAPD loci that were all polymorphic. By analysis of RAPD data with POPGENE software, it was found that high level of genetic diversity existed in S. grandis populations. Most variation existed within populations and 28% variation existed among populations. By Pearson correlation analysis, significant correlations were found between gene diversity indexes and temperature factors （ ≥ 10℃ cumulative temperature in a year, annual mean temperature and mean temperature in January）, and all diversity indexes showed significant correlations with mean temperature in January. Mantel tests showed that there was no significant correlation between Nei＇s unbiased genetic distance and geographic distance of S.grandis populations, but positive and significant correlations existed between Nei＇ s genetic distance and several climatic divergences in pair-wise S. grandis populations （ p 〈 0.05）, suggesting that natural selection of climatic variation （ mainly in precipitation and temperature） resulted in the adaptive RAPD eco-geographic differentiation.
出处
《生态学报》
CAS
CSCD
北大核心
2006年第5期1312-1319,共8页
Acta Ecologica Sinica
基金
国家重点基础研究发展规划资助项目(G2000018601)~~
关键词
大针茅
建群种
RAPD
遗传多样性
气候因子
自然选择
Stipa grandis P. Smirn.
dominant species
RAPD
genetic diversity
climatic factor
natural selection
