Ganal M W, Bonierbale M W, Roeder M S, Park W D, Tanksley S D
Department of Plant Breeding and Biometry, Cornell University, Ithaca, NY 14853.
Mol Gen Genet. 1991 Mar;225(3):501-9. doi: 10.1007/BF00261693.
Genes for the major storage protein of potato, patatin, have been mapped genetically and physically in both the potato and tomato genomes. In potato, all patatin genes detected by the cDNA clone pGM01 map to a single locus at the end of the long arm of chromosome 8. By means of pulsed field gel electrophoresis (PFGE) it was possible further to delimit this locus, containing 10-15 copies of the gene, to a maximum size of 1.4 million base pairs. Hybridizations with class-specific clones suggest that the locus is at least partially divided into domains containing the two major types of patatin genes, class I and II. In tomato, patatin-homologous sequences were found to reside at the orthologous locus at the end of chromosome 8. The approximately three copies in tomato were localized by PFGE to a single fragment of 300 kilobases. Whereas the class II-specific 5' promoter sequences reside in tomato at the same locus as the coding sequences, the single class I-specific copy of the 5' promoter sequences was localized on chromosome 3 with no coding sequence attached to it. A clone from this chromosome 3 locus of tomato was isolated and by restriction fragment length polymorphism mapping it could be further shown that a similar class I-specific sequence also exists on chromosome 3 of potato. As in tomato, this copy on chromosome 3 is not linked to a coding sequence for patatin. The results are discussed with respect to genome evolution and PFGE analysis of complex gene families.
马铃薯主要贮藏蛋白（即马铃薯块茎蛋白）的基因已在马铃薯和番茄基因组中进行了遗传定位和物理定位。在马铃薯中，由cDNA克隆pGM01检测到的所有马铃薯块茎蛋白基因都定位于8号染色体长臂末端的一个单一基因座。通过脉冲场凝胶电泳（PFGE），有可能进一步将这个包含该基因10 - 15个拷贝的基因座限定到最大140万个碱基对的大小。与类别特异性克隆的杂交表明，该基因座至少部分地被划分为包含两类主要马铃薯块茎蛋白基因（I类和II类）的结构域。在番茄中，发现马铃薯块茎蛋白同源序列位于8号染色体末端的直系同源基因座上。番茄中大约三个拷贝通过PFGE定位到一个300千碱基的单一片段上。虽然II类特异性的5'启动子序列在番茄中与编码序列位于同一基因座，但I类特异性的5'启动子序列的单个拷贝定位于3号染色体上，且没有与之相连的编码序列。从番茄的这个3号染色体基因座分离出一个克隆，通过限制性片段长度多态性图谱分析进一步表明，马铃薯的3号染色体上也存在类似的I类特异性序列。与番茄一样，3号染色体上的这个拷贝不与马铃薯块茎蛋白的编码序列相连。本文就复杂基因家族的基因组进化和PFGE分析对这些结果进行了讨论。
