据一项由加州大学河滨分校（UCR）科学家带领的研究小组报告，他们已经绘制出豇豆的高密度连锁图谱（Vigna unguiculata）。豇豆是一种蛋白质丰富的豆类作物，在数百万人的饮食和经济中发挥了重要作用。由于其顽强的品质，豇豆在维持亚洲和拉丁美洲的干旱易发地区，特别是撒哈拉以南非洲地区的粮食安全方面发挥了关键作用。尽管很重要，但有关豇豆的可参考的基因组信息却很有限。
研究人员整合了183000多种能够识别可能标记的表达序列标签(ESTs)的序列数据。从这些ESTs得到的SNP信息中获取了10000个高信任的SNPs，从而开发了Illumina公司的GoldenGate基因型芯片。研究人员接着应用这些芯片检测了来自6个正在图谱绘制中的品种的741个重组杂交系，他们发现约90％的SNP位点可认为是豇豆的遗传标记。约900种这些标记被整合到这张高密度连锁图谱中。由此产生的图谱长680cm，包括11个连锁群，标记的平均距离为0.73cm。
研究人员发现豇豆与大豆的基因组非常相关。“在物种之间有相当的基因序列是保守的”， 加州大学的研究员Philip Roberts说，“通过在红豆染色体中寻找标记，我们可以相互参考这些标记信息，例如研究大豆中基于DNA序列的标记。这些将有利于知识在物种之间的交流，在红豆研究中取得的进展可以转化为大豆研究的有益信息，反之亦然。”（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS October 13, 2009, doi: 10.1073/pnas.0905886106
A consensus genetic map of cowpea [Vigna unguiculata (L) Walp.] and synteny based on EST-derived SNPs
Wellington Mucheroa,1, Ndeye N. Diopb,1, Prasanna R. Bhatb,2, Raymond D. Fentonb, Steve Wanamakerb, Marti Pottorffb, Sarah Hearnec, Ndiaga Cissed, Christian Fatokunc, Jeffrey D. Ehlersb, Philip A. Robertsa and Timothy J. Closeb,3
aDepartments of aNematology and
bBotany and Plant Sciences, University of California, Riverside, CA 92521;
cThe International Institute of Tropical Agriculture, Oyo Road, PMB 5320, Ibadan, Nigeria; and
dSenegalese Institute of Agricultural Research, Bambey, Senegal
Consensus genetic linkage maps provide a genomic framework for quantitative trait loci identification, map-based cloning, assessment of genetic diversity, association mapping, and applied breeding in marker-assisted selection schemes. Among “orphan crops” with limited genomic resources such as cowpea [Vigna unguiculata (L.) Walp.] (2n = 2x = 22), the use of transcript-derived SNPs in genetic maps provides opportunities for automated genotyping and estimation of genome structure based on synteny analysis. Here, we report the development and validation of a high-throughput EST-derived SNP assay for cowpea, its application in consensus map building, and determination of synteny to reference genomes. SNP mining from 183,118 ESTs sequenced from 17 cDNA libraries yielded ≈10,000 high-confidence SNPs from which an Illumina 1,536-SNP GoldenGate genotyping array was developed and applied to 741 recombinant inbred lines from six mapping populations. Approximately 90% of the SNPs were technically successful, providing 1,375 dependable markers. Of these, 928 were incorporated into a consensus genetic map spanning 680 cM with 11 linkage groups and an average marker distance of 0.73 cM. Comparison of this cowpea genetic map to reference legumes, soybean (Glycine max) and Medicago truncatula, revealed extensive macrosynteny encompassing 85 and 82%, respectively, of the cowpea map. Regions of soybean genome duplication were evident relative to the simpler diploid cowpea. Comparison with Arabidopsis revealed extensive genomic rearrangement with some conserved microsynteny. These results support evolutionary closeness between cowpea and soybean and identify regions for synteny-based functional genomics studies in legumes.
