炎炎夏日，以西瓜为代表的各种瓜类成为人们最爱。美国科研人员最新报告说，他们绘制出了西瓜等瓜类的基因组图谱，将来有望利用基因技术开发出更甜、更可口、更健康的瓜类新品种。
得克萨斯农机大学科研人员在新一期《美国园艺科学协会杂志》上报告说，此前法国和西班牙研究人员曾经完成了瓜类某些DNA（脱氧核糖核酸）片段的图谱绘制工作。而得克萨斯农机大学研究小组在此基础上通过瓜类杂交，得出了瓜类的完整基因组图谱。
研究人员说，除了瓜类的完整基因组信息，他们还在实验中识别出了瓜类的一些最重要基因，比如负责调控糖分的基因、与维生素C有关的基因等，这些对于培育新的瓜类杂交品种都十分有用。下一步，研究人员还将从基因组图谱中识别出与瓜类抗病、耐旱、形状、大小等有关的各种基因。（生物谷Bioon.com）
生物谷推荐原始出处：
J. Amer. Soc. Hort. Sci. 134: 67-76 (2009)
A Genetic Linkage Map including Loci for Male Sterility, Sugars, and Ascorbic Acid in Melon
Soon O. Park1, Hye Y. Hwang and Kevin M. Crosby
Vegetable & Fruit Improvement Center, Texas A&M University, College Station, TX 77845; Texas AgriLife Research and Extension Center, Texas A&M System, Weslaco, TX 78596; and the Department of Horticultural Sciences, Texas A&M University, College Station, TX 77845
Our objectives were to construct a randomly amplified polymorphic DNA (RAPD) marker-based linkage map using an F2 population derived from the melon (Cucumis melo) cross of ‘Deltex’ x TGR 1551, and map quantitative trait loci (QTL) for sucrose, total soluble solids (TSS), ratio of sucrose to total sugars (RSTS), and ascorbic acid as well as the ms-3 locus for male sterility previously reported in other muskmelon crosses. Due to the dominant character of RAPD markers, we scored 192 ‘Deltex’- and 158 TGR 1551-derived markers. One hundred eighty (94%) of the 192 markers fit the expected 3:1 ratio. On the basis of the 180 markers, we constructed a ‘Deltex’ linkage map of 171 markers distributed on 12 linkage groups (LGs) with a total map distance of 1182 cM. One hundred fifty (95%) of the 158 markers were identified to be nondistorted. We developed a TGR 1551 linkage map of 138 markers distributed on 12 LGs with a total distance of 1163 cM. A combined map of 12 LGs with a total map distance of 1394 cM was made from 82 marker pairs expressing codominance. Nine LGs were integrated into those of the existing composite map by 17 anchor markers. We mapped the ms-3 locus for male sterility on LG 9, which corresponds to LG 10 of the classical map and LG VII of the composite map. Six QTL for sucrose were located on LGs 2, 3, 4, 6, and 11. Three on LGs 3, 4, and 6 and four on LGs 2, 3, 6, and 11 of the six QTL for sucrose were also noted to be QTL for TSS and RSTS, respectively. A single QTL for ascorbic acid was placed on LG 5. This map will also be used to identify QTL for fruit sweetness, quality, size, and shape traits, as well as disease resistance.
