Screeing Of Genome Specific Repetitive Sequence Related With G.Barbadense And Subcloning Analysis

In this study, the genome of G.barbadense was used to isolate specific repetitive sequence. Repeated sequence distribution in G.barbadense, G.arboreum, G.herbaceum, G.herbaceum var.africanum and G.raimondii were verified by FISH after constrction of subclones and sequence analysis.The main results were obtained as follows:1.19,200 BAC clones were screened from pima90-53 BAC library. Fluorescence in situ hybridization (FISH) was carried out on G..barbadense mitotic metaphase chromosomes by using the probes of specific repetitive sequence.According to the distribution of hybridization signal, we found four BAC monoclonal.The clone numbers are:428K20,412A1l,334E15,216B18.2. In situ hybridization results showed that 428K20 can produce strong signal in all the chromosomes of G.barbadense,428K20 produced a strong hybridization signal in besides the chromosome ends large chromosomes (A subgenome) of G.barbadense. However, hybridization signal could be found in the region near the centromere of small chromosomes (D subgenome).In G.arboreum, the signal distribution in accordance with large chromosomes (A subgenome)of G.barbadense but it can't produce hybridization signal in G.raimondii;422Al1 only was produced hybridization signal in large the chromosome(A subgenome) ends of G.barbaddense.It also could be produced hybridization signal in the chromosome ends of G.arboreum,G. herbaceum,Gherbaceum var.africanum. But it didn't produce hybridization signal in G.raimondii.It is therefore confirm that 428K20 and 412A11 are specific repetitive sequence of A genome,but 428K20 contains a transpositional element(sequence);334E15 produced hybridization signal in besides the chromosome ends large chromosomes(A subgenome)of G.barbadense,especially hybridization signal were very strong in the middle of large chromosome(A subgenome). Such BAC clones may be more relevant in the pima90-53 BAC library.It is a typical A subgenome specific repeat sequence;216B18 can produce hybridization signal in all the chromosome of G.Barbadense but six strong hybridization signal which are located at the ends of six chromosome. Such BAC clones may be also more relevant in the pima90-53 BAC library.According to hybridization signal,216B18 mainly contains 45S of repetitive sequence and a kind of interspersed repeat sequences which are distributed in all chromosomes of G.barbadense.3.428K20 and 412A11 was only constructed subclone library. The result of subcloning sequencing data indicated that 428K20 were contain mGhCIR291, JESPR272,LIB5327-017-A1-N1-D12_P_S_Gh557 of micro-satellite sequences and gypsy-like retrotransposon in G..hirsutum,Gypsy-like retrotransponson may attended invasion from large chromosomes(A subgenome)to small chromosomes(D subgenome). While 412A11 was primarily predicted genes predicted protein, mRNA expression and miniature inverted repeat transposable element (MITE) of G..hirsutum. According to hybridization signal of A genome chromosomes, it is inferred that telomere or subtelomeric regions of A genome chromosomes may be contain miniature inverted repeat t ransposable element (MITE).