A saturated genetic linkage map of autotetraploid alfalfa (Medicago sativa L.) developed using genotyping-by-sequencing is highly syntenous with the Medicago truncatula genome.
A saturated genetic linkage map of autotetraploid alfalfa (Medicago sativa L.) developed using genotyping-by-sequencing is highly syntenous with the Medicago truncatula genome.
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DOI：
10.1534/g3.114.012245
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发表时间：
2014-08-21
期刊：
影响因子：
--
通讯作者：
Brummer EC
中科院分区：
文献类型：
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作者：
Li X;Wei Y;Acharya A;Jiang Q;Kang J;Brummer EC
遗传连锁图谱是数量性状基因座作图、基于图谱的基因克隆、比较作图和全基因组组装的重要工具。苜蓿是世界上最重要的饲料作物之一，其具有同源四倍体、同源异源和高度杂合的特征，这些特征阻碍了使用传统遗传标记系统构建高密度连锁图谱。利用测序基因分型 (GBS)，我们为同源四倍体苜蓿 F1 群体的母本和父本亲本基因组构建了低成本、相当高密度的连锁图谱。所得图谱在父母双方的 64 个连锁群上包含 3591 个单核苷酸多态性标记，母本和父本单倍型图谱的平均密度分别为每 1.5 和 1.0 cM 1 个标记。根据标记与蒺藜 M. truncatula 基因组的同源性进行染色体分配。代表每个苜蓿染色体的四个单倍型的四个连锁群被分配给母本和父本的八个苜蓿染色体中的每一个。苜蓿连锁群与蒺藜苜蓿高度同线性，并清楚地识别出 4 号和 8 号染色体之间已知的易位。此外，在蒺藜苜蓿和苜蓿之间还发现了 1 号染色体上的小倒位。 GBS 使我们能够开发出苜蓿的饱和连锁图谱，与之前的图谱相比，该图谱大大提高了基因组覆盖度，并将有利于基因组结构的研究。 GBS 可用于育种群体，以加速苜蓿的分子育种。
A genetic linkage map is a valuable tool for quantitative trait locus mapping, map-based gene cloning, comparative mapping, and whole-genome assembly. Alfalfa, one of the most important forage crops in the world, is autotetraploid, allogamous, and highly heterozygous, characteristics that have impeded the construction of a high-density linkage map using traditional genetic marker systems. Using genotyping-by-sequencing (GBS), we constructed low-cost, reasonably high-density linkage maps for both maternal and paternal parental genomes of an autotetraploid alfalfa F1 population. The resulting maps contain 3591 single-nucleotide polymorphism markers on 64 linkage groups across both parents, with an average density of one marker per 1.5 and 1.0 cM for the maternal and paternal haplotype maps, respectively. Chromosome assignments were made based on homology of markers to the M. truncatula genome. Four linkage groups representing the four haplotypes of each alfalfa chromosome were assigned to each of the eight Medicago chromosomes in both the maternal and paternal parents. The alfalfa linkage groups were highly syntenous with M. truncatula, and clearly identified the known translocation between Chromosomes 4 and 8. In addition, a small inversion on Chromosome 1 was identified between M. truncatula and M. sativa. GBS enabled us to develop a saturated linkage map for alfalfa that greatly improved genome coverage relative to previous maps and that will facilitate investigation of genome structure. GBS could be used in breeding populations to accelerate molecular breeding in alfalfa.