番茄和桃基因组的微同线性研究

Microsynteny analysis of tomato and peach genome

番茄和桃是茄科和蔷薇科的重要模式植物。近年来,随着它们基因组测序工作的展开,相关基因组序列快速累积,为番茄和桃遗传图谱和物理图谱的比较分析及深入了解其进化关系提供了可能。文章对番茄和桃的基因组进行了比较,通过番茄遗传图谱与桃物理图谱、番茄物理图谱与桃遗传图谱以及番茄物理图谱与桃物理图谱等3个层面的数据比对分析,结果揭示在这两个基因组间存在着大量的微同线性片段。这些同线性片段中所包含的保守同源基因对的数目较少(总计297个同线性片段中仅有36个片段包含有两个以上的同源基因对)。这些同线性片段都是小范围的,并且有部分微同线性片段在不同的染色体或者BACcontig之间构成了一个相互关联的网络结构。通过与番茄的EST文库比对,发现了9个与果实发育和成熟相关的微同线性基因。这些微同线性基因的发现对于进一步研究这两个亲缘关系比较远的物种在果实发育与成熟方面的共性提供了线索。

Tomato and peach are two important model species belonging to the families Solanaceae and Rosaceae, respectively. Recently, more and more sequence data generated from their whole genome sequencing projects can be used for bioinformatic analysis. Microsynteny analysis for tomato and peach were conducted to detect conserved syntenic blocks using high quality genetic and physical maps. A large number of microsyntenic regions were detected through three comparisons： comparison between tomato genetic map and peach physical map, between tomato physical map and peach genetic map, and between tomato physical map and peach physical map. Most of the syntenic blocks were short, and each block contained a small number of conserved gene pairs （261 syntenic blocks with only two homolog pairs, and 36 syntenic blocks with more than two homolog pairs）. Tomato and peach had noncontinuous fragmentary microsynteny and some syntenic groups composed of complex networks among different chromosomes or BAC contigs. After comparing the homologous proteins with tomato fruit-related EST libraries, a total of 9 proteins were found in different syntenic groups relating to fruit development and ripening. Microsynteny identified in this study could facilitate further investigation of fruit development and ripening in these two distantly related species.