Zhou Yi, Gwaze David P, Reyes-Valdés M Humberto, Bui Thomas, Williams Claire G
Forest Genetics Program, Texas A&M University, College Station, TX 77843-2135, USA.
Genome. 2003 Oct;46(5):809-16. doi: 10.1139/g03-062.
Clustering has been reported for conifer genetic maps based on hypomethylated or low-copy molecular markers, resulting in uneven marker distribution. To test this, a framework genetic map was constructed from three types of microsatellites: low-copy, undermethylated, and genomic. These Pinus taeda L. microsatellites were mapped using a three-generation pedigree with 118 progeny. The microsatellites were highly informative; of the 32 markers in intercross configuration, 29 were segregating for three or four alleles in the progeny. The sex-averaged map placed 51 of the 95 markers in 15 linkage groups at LOD > 4.0. No clustering or uneven distribution across the genome was observed. The three types of P. taeda microsatellites were randomly dispersed within each linkage group. The 51 microsatellites covered a map distance of 795 cM, an average distance of 21.8 cM between markers, roughly half of the estimated total map length. The minimum and maximum distances between any two bins was 4.4 and 45.3 cM, respectively. These microsatellites provided anchor points for framework mapping for polymorphism in P. taeda and other closely related hard pines.
据报道，基于低甲基化或低拷贝分子标记构建的针叶树遗传图谱存在聚类现象，导致标记分布不均。为了验证这一点，利用三种类型的微卫星构建了一个框架遗传图谱：低拷贝、低甲基化和基因组微卫星。这些火炬松微卫星使用一个具有118个后代的三代谱系进行定位。这些微卫星具有高度的信息性；在杂交配置的32个标记中，有29个在后代中分离出三个或四个等位基因。性别平均图谱将95个标记中的51个置于15个连锁群中，LOD>4.0。未观察到全基因组的聚类或分布不均。三种类型的火炬松微卫星在每个连锁群内随机分布。这51个微卫星覆盖的图谱距离为795厘摩，标记间平均距离为21.8厘摩，约为估计总图谱长度的一半。任意两个区间之间的最小和最大距离分别为4.4厘摩和45.3厘摩。这些微卫星为火炬松和其他近缘硬松的多态性框架图谱提供了锚定位点。
