據(jù)一項(xiàng)由加州大學(xué)河濱分校（UCR）科學(xué)家?guī)ьI(lǐng)的研究小組報(bào)告，他們已經(jīng)繪制出豇豆的高密度連鎖圖譜（Vigna unguiculata）。豇豆是一種蛋白質(zhì)豐富的豆類作物,，在數(shù)百萬(wàn)人的飲食和經(jīng)濟(jì)中發(fā)揮了重要作用。由于其頑強(qiáng)的品質(zhì),，豇豆在維持亞洲和拉丁美洲的干旱易發(fā)地區(qū),，特別是撒哈拉以南非洲地區(qū)的糧食安全方面發(fā)揮了關(guān)鍵作用。盡管很重要,，但有關(guān)豇豆的可參考的基因組信息卻很有限,。
研究人員整合了183000多種能夠識(shí)別可能標(biāo)記的表達(dá)序列標(biāo)簽(ESTs)的序列數(shù)據(jù)。從這些ESTs得到的SNP信息中獲取了10000個(gè)高信任的SNPs,，從而開發(fā)了Illumina公司的GoldenGate基因型芯片,。研究人員接著應(yīng)用這些芯片檢測(cè)了來(lái)自6個(gè)正在圖譜繪制中的品種的741個(gè)重組雜交系，他們發(fā)現(xiàn)約90％的SNP位點(diǎn)可認(rèn)為是豇豆的遺傳標(biāo)記,。約900種這些標(biāo)記被整合到這張高密度連鎖圖譜中,。由此產(chǎn)生的圖譜長(zhǎng)680cm，包括11個(gè)連鎖群,，標(biāo)記的平均距離為0.73cm,。
研究人員發(fā)現(xiàn)豇豆與大豆的基因組非常相關(guān)。“在物種之間有相當(dāng)?shù)幕蛐蛄惺潜Ｊ氐?rdquo;,， 加州大學(xué)的研究員Philip Roberts說(shuō),，“通過(guò)在紅豆染色體中尋找標(biāo)記，我們可以相互參考這些標(biāo)記信息,，例如研究大豆中基于DNA序列的標(biāo)記,。這些將有利于知識(shí)在物種之間的交流，在紅豆研究中取得的進(jìn)展可以轉(zhuǎn)化為大豆研究的有益信息,，反之亦然,。”（生物谷Bioon.com）
生物谷推薦原始出處：
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.
