摘要
对于杉木 1∶1分离的分子标记位点 ,提出了一种新的构建遗传连锁图谱的策略。通过二点连锁分析 ,任意两个位点的连锁相和重组率可以得到推断和估计。对于一个连锁群中的最优排序 ,采用隐马尔可夫链模型的方法进行多位点的连锁分析。该作图方法比通常林木上所用的“拟测交”作图方法更有效。采用该作图策略 ,利用句容0号无性系 (♀ )×柔叶杉 (♂ )的F1代群体的AFLP分子标记数据重建了句容 0号无性系和柔叶杉的遗传连锁图谱。在句容 0号无性系的连锁图谱中 ,有 10 1个标记分布在 11个连锁群上 ,图谱的总长度为 2 2 82 6cM ,平均图距为 2 2 6cM ,单个连锁群上最多含有 17个标记 ,最少含有 5个标记 ;在柔叶杉的连锁图谱中 ,有 94个标记分布在 11个连锁群上 ,图谱的总长度为 2 5 6 5 8cM ,平均图距为 2 7 3cM ,单个连锁群上最多含有 16个标记 ,最少含有 4个标记。构建的句容 0号无性系和柔叶杉的遗传连锁图谱比原有的图谱分别增加了 2 6个标记和 2 8个标记 ,双亲的图谱共增加了 5 4个AFLP标记 ,使图谱上的分子标记总数达到 195个 ,双亲遗传图谱的跨度均超过了 2 0 0 0cM ,基本上达到了杉木基因组的长度 ,图谱的覆盖率接近于 10 0 %。利用新的作图方法可以较大提高分子标记在图谱上的分辨率 。
A new strategy was proposed for constructing linkage maps for 1∶1 segregation molecular markers in Chinese fir.Linkage phase and recombination ratio for any two loci can be inferred and estimated.For the best order in a linkage group,the Hidden Markov Chain Model was used for multilocus linkage analysis.The mapping method proposed here was more effective than the 'pseudo-testcross' method commonly used in forest trees.In this paper,with the AFLP marker data obtained from the F_1 progeny of 'Jurong 0' (♀)×'Rouye'(♂),the genetic linkage maps of the Chinese fir clones,'Jurong 0' and 'Rouye',were reconstructed based on the new mapping method.In the genetic linkage map of 'Jurong 0',101 markers were distributed in 11 linkage groups with an average distance of 22.6 cM and a total length of 2 282.6 cM.There were as many as 17 markers and as few as 5 markers in single linkage groups of the map.In the genetic linkage map of 'Rouye',94 markers were distributed in the 11 linkage groups with an average distance of 27.3 cM and a total length of 2 565.8 cM.There were as many as 16 markers and as few as 4 markers in single linkage groups of the map.Compared with the 'pseudo- testcross' method,the two maps increased 26 markers and 28 markers,respectively,and totally 54 markers were added.The two maps contained 195 AFLP markers and each spanned more than 2 000 cM,almost covering the whole genome of Chinese fir.Therefore,the resolutions of linkage maps of Chinese fir 'Jurong 0' and 'Rouye' were improved with the new mapping method,and the maps provide the framework for further genetic analysis.
基金
国家重点基础研究规划"973"项目 (编号 :TG19990 160 0 4)
江苏省基础研究计划项目 (编号 :BK2 0 0 3 0 98)资助~~
