Study On The Key Components Of Plant Choromosome: The Sequence Of Telomere And Centromere

Telomeres are special functional structure at the end of chromosomes and have been thought to protect the chromosome ends from degradation and fusion to other linear chromosomes. It is mainly composed of G-rich short tandem repeated sequences with units length range from five to seven bases pairs. Through G-G pairings, telomere formed four-stranded parallel G4 DNA formation which can efficiently resist to restrictive endonucleases. But on the other hand, this G-G pairings of telomeric sequences also facilitate slippage and loss of the repeats during DNA replication in E.coil where replication proceeded with DNA polymerase rather than telomerase.Centromeres are characteristic features of chromosomes, and can attache to spindle microtubules through a proteinaceous structure referred to as the kinetochore during both meiosis and mitosis. They are important for chromosomes' segregation properly. But due to challenges in sequence analysis, namely centromere repeated sequences are difficult to construct sequencing contig, even no one centromeres are completely sequenced out today. So, described very early by scientist, yet centromeres still turned to the final frontier of eukaryotic genomes. More mysteriously, authough its' function is conserved throughout eukaryotic biology, centromeric DNA actually are among the most quickly evolved and divergent ones. In Arabidopsis, the length of centromeric satellite DNA repeat is 178 base pairs. The genome project of Arabidopsis finishing makes Cruciferae family most suitable to investigate the molecular evolution of centromeric satellite repeats in plants. Further sequences of centromeric DNA from species can assist in gaining insight into the evolution, diversification and functional role of centromeric sequences and can help to classificate the species following evolutionary relationships anew.We have cloned the Arabidopsis telomere sequence through ligation blunting telomeric PCR products into vectors and study the loss laws of telomere sequences in E.coil. In some degree, the results of our research maybe could give some help to one who also want to acquire E.coil clones inserted of short repeat sequence. Using the...