Cheng Yan, Geng Jianfeng, Zhang Jingyi, Wang Qian, Ban Qingyu, Hou Xilin
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
J Genet Genomics. 2009 Aug;36(8):501-8. doi: 10.1016/S1673-8527(08)60140-X.
Non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid (DH) lines, and the DH population was derived from a commercial hybrid "Hanxiao" (lines SW-13 x L-118). Out of the 614 polymorphic markers, 43.49% were not assigned to any of the linkage groups(LGs). Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on common simple sequence repeat (SSR) markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 (R08) to 64 (R07), with an average interval distance within a single LG from 1.70 cM (R07) to 6.71 cM (R06). Among these mapped markers, 169 were sequence-related amplified polymorphism (SRAP) molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA (RAPD) markers. With further saturation to the LG, the current map offers a genetic tool for loci analysis for important agronomic traits.
不结球白菜（Brassica campestris ssp. chinensis Makino）是中国东部最重要的蔬菜之一。利用127个双单倍体（DH）系构建了遗传连锁图谱，该DH群体源自商业杂交种“汉小”（品系SW - 13×L - 118）。在614个多态性标记中，43.49%未被分配到任何连锁群（LG）中。卡方检验表明，42.67%的标记偏离了预期的孟德尔分离比，分离扭曲方向主要偏向父本L - 118。从上游标记开始依次去除间隔距离小于1 cM的标记后，连锁图谱的整体质量得到了提高。268个分子标记被定位到10个LG上，基于共同的简单序列重复（SSR）标记将这些LG锚定到白菜参考图谱的相应染色体上。该图谱覆盖了973.38 cM的基因组，标记间的平均间隔距离为3.63 cM。每个LG上的标记数量从18个（R08）到64个（R07）不等，单个LG内的平均间隔距离从1.70 cM（R07）到6.71 cM（R06）。在这些定位的标记中，169个是序列相关扩增多态性（SRAP）分子标记，50个是SSR标记，49个是随机扩增多态性DNA（RAPD）标记。随着LG的进一步饱和，当前图谱为重要农艺性状的基因座分析提供了一种遗传工具。
