人力資源與數位學習科技研究所

Abstract

　　Rice shares synteny with other economic crops, the analysis of rice genome structure will help us to understand the genomic organization of the other crops. Rice genome size is the smallest among the cereal crops. Despite its small size, rice genome contains a wide variety of transposable elements (TEs). TEs are divided into two main classes according to their structural organization and mechanism of transposition. Class I elements, known as retrotransposons, are transposed through an RNA intermediate. Based on the structural organization, retrotransposons could be further classified into copia, gypsy, and the non-LTR restrotransposon. Class II elements are transposed through a DNA intermediate by an excision/repair mechanism. Based on the homology of terminal inverted repeats (TIRs) and the lengths of target site duplications (TSDs) upon transposition, class II TEs in plants have been classified into various families such as Ac/Ds family, CACTA family (En/Spm family), and Mutator-like elements (MULEs). The miniature inverted repeat transposable element (MITE) has been identified as another type of class II element. Several models, such as the deleterious insertion model or the ectopic exchange model, have been proposed for natural selection against the genome abundance of TEs. Using high-quality genomic sequences, physical and genetic maps, we analyzed the distribution of various TE families through the whole rice genome and explored factors that shape the insertion patterns of rice TEs.