Rouppe van der Voort J N, van Eck H J, van Zandvoort P M, Overmars H, Helder J, Bakker J
Graduate School of Experimental Plant Sciences, Department of Nematology, Wageningen Agricultural University, The Netherlands.
Mol Gen Genet. 1999 Jul;261(6):1021-31. doi: 10.1007/s004380051051.
A mapping strategy is described for the construction of a linkage map of a non-inbred species in which individual offspring genotypes are not amenable to marker analysis. After one extra generation of random mating, the segregating progeny was propagated, and bulked populations of offspring were analyzed. Although the resulting population structure is different from that of commonly used mapping populations, we show that the maximum likelihood formula for a normal F2 is applicable for the estimation of recombination. This "pseudo-F2" mapping strategy, in combination with the development of an AFLP assay for single cysts, facilitated the construction of a linkage map for the potato cyst nematode Globodera rostochiensis. Using 12 pre-selected AFLP primer combinations, a total of 66 segregating markers were identified, 62 of which were mapped to nine linkage groups. These 62 AFLP markers are randomly distributed and cover about 65% of the genome. An estimate of the physical size of the Globodera genome was obtained from comparisons of the number of AFLP fragments obtained with the values for Caenorhabditis elegans. The methodology presented here resulted in the first genomic map for a cyst nematode. The low value of the kilobase/centimorgan (kb/cM) ratio for the Globodera genome will facilitate map-based cloning of genes that mediate the interaction between the nematode and its host plant.
本文描述了一种用于构建非自交物种连锁图谱的定位策略，该物种的个体后代基因型不适用于标记分析。经过额外一代的随机交配后，对分离的后代进行繁殖，并对后代的混合群体进行分析。尽管所得的群体结构与常用的定位群体不同，但我们表明，正常F2的最大似然公式适用于重组估计。这种“假F2”定位策略，结合针对单个孢囊的AFLP分析方法，促进了马铃薯孢囊线虫罗氏 Globodera rostochiensis 连锁图谱的构建。使用12个预先选择的AFLP引物组合，共鉴定出66个分离标记，其中62个被定位到9个连锁群。这62个AFLP标记随机分布，覆盖约65%的基因组。通过将获得的AFLP片段数量与秀丽隐杆线虫Caenorhabditis elegans 的值进行比较，获得了对Globodera基因组物理大小的估计。本文介绍的方法产生了第一个孢囊线虫的基因组图谱。Globodera基因组的千碱基/厘摩（kb/cM）比值较低，这将有助于基于图谱克隆介导线虫与其寄主植物之间相互作用的基因。
