Farman M L, Leong S A
Department of Plant Pathology, University of Wisconsin, Madison 53706, USA.
Genetics. 1995 Jun;140(2):479-92. doi: 10.1093/genetics/140.2.479.
Telomeric restriction fragments were genetically mapped to a previously described linkage map of Magnaporthe grisea, using RFLPs identified by a synthetic probe. (TTAGGG)3. Frequent rearrangement of telomeric sequences was observed in progeny isolates creating a potential for misinterpretation of data. Therefore a consensus segregation data set used to minimize mapping errors. TWelve of the 14 telomeres were found to be genetically linked to existing RFLP markers. Second-dimensional electrophoresis of restricted chromosomes confirmed these linkage assignments and revealed the chromosomal location of the two unlinked telomeres. We were thus able to assign all 14 M. grisea telomeres to their respective chromosome ends. The Achilles' cleavage (AC) technique was employed to determine that chromosome 1 markers 11 and CH5-120H were approximately 1.8 Mb and 1.28 Mb, respectively, from their nearest telomeres. RecA-AC was also used to determine that unlinked telomere 6 was approximately 530 kb from marker CH5-176H in strain 2539 and 580 kb in Guy11. These experiments indicated that large portions of some chromosome ends are unrepresented by genetic markers and provided estimates of the relationship of genetic to physical distance in these regions of the genome.
使用由合成探针（TTAGGG）3鉴定的限制性片段长度多态性（RFLP），将端粒限制性片段基因定位到先前描述的稻瘟病菌连锁图谱上。在子代分离物中观察到端粒序列频繁重排，这可能导致数据解读错误。因此，使用了一个共分离数据集来尽量减少定位误差。14个端粒中的12个被发现与现有的RFLP标记基因连锁。限制性染色体的二维电泳证实了这些连锁关系，并揭示了两个未连锁端粒的染色体位置。因此，我们能够将稻瘟病菌的所有14个端粒定位到它们各自的染色体末端。采用阿喀琉斯切割（AC）技术确定，在菌株2539中，1号染色体上的标记11和CH5 - 120H分别距离其最近的端粒约1.8 Mb和1.28 Mb。RecA - AC也被用于确定，在菌株2539中，未连锁的端粒6距离标记CH5 - 176H约530 kb，在Guy11中约580 kb。这些实验表明，一些染色体末端的大部分区域没有遗传标记覆盖，并提供了这些基因组区域中遗传距离与物理距离关系的估计。
