Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two cen...Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two centromeric repeats （RCS1 and CCS1-5ab） to obtain some centromere-assoclated bacterial artificial chromosome （BAC） clones in 32 RCS1-related BAC clones that had been screened out from a diploid wheat （Triticum boeoticum Boiss.; 2n=2x=14） BAC library. Southern hybridization results indicated that, of the 32 candidates, there were 28 RCS1-positive clones. Based on gel blot patterns, the frequency of RCS1 was approximately one copy every 69.4 kb in these 28 RCS1-positive BAC clones. More bands were detected when the same filter was probed with CCS1-5ab. Furthermore, the CCS1 bands covered all the bands detected by RCS1, which suggests that some CCS1 repeats were distributed together with RCS1. The frequency of CCS1 families was once every 35.8 kb, nearly twice that of RCS1. Fluorescence in situ hybridization （FISH） analysis Indicated that the five BAC clones containing RCS1 and CCS1 sequences all detected signals at the centromerlc regions in hexaplold wheat, but the signal intensities on the A-genome chromosomes were stronger than those on the B- and/or Dgenome chromosomes. The FISH analysis among nine Triticeae cereals indicated that there were A-genomespecific （or rich） sequences dispersing on chromosome arms in the BAC clone TbBACS. In addition, at the interphase cells, the centromeres of diploid species usually clustered at one pole and formed a ring-like allocation In the period before metaphase.展开更多
A bacterial artificial chromosome library has been constructed for Triticum boeoticum Boiss (A bA b) using the bacterial artificial chromosome (BAC) vector pECBAC1. The library consists of about 170 000 clones. A ...A bacterial artificial chromosome library has been constructed for Triticum boeoticum Boiss (A bA b) using the bacterial artificial chromosome (BAC) vector pECBAC1. The library consists of about 170 000 clones. A random sampling analysis of 200 BAC clones indicates that the average insert size is 104 kb. Based on the genome size of T. boeoticum, the library is about three times as large as T. boeoticum haploid genome (5 600 Mb). Screening the BAC library with cpDNA sequence psbA gene and mtDNA sequence atp6 gene as probe shows that contamination of the library with chloroplast and mitochondrial clones is less than 1%. The library will be a useful platform in gene clone and genomic research of wheat.展开更多
Although Iran is a main center of distribution of wild wheats, but little information is available regarding genetic variation in wild wheat relatives from this country (Tabatabaei and Massoumi, 2001). The habitats of
文摘Although the centromeres of some plants have been investlgated prevlously, our knowledge of the wheat centromere Is still very llmlted. To understand the structure and functlon of the wheat centromere, we used two centromeric repeats （RCS1 and CCS1-5ab） to obtain some centromere-assoclated bacterial artificial chromosome （BAC） clones in 32 RCS1-related BAC clones that had been screened out from a diploid wheat （Triticum boeoticum Boiss.; 2n=2x=14） BAC library. Southern hybridization results indicated that, of the 32 candidates, there were 28 RCS1-positive clones. Based on gel blot patterns, the frequency of RCS1 was approximately one copy every 69.4 kb in these 28 RCS1-positive BAC clones. More bands were detected when the same filter was probed with CCS1-5ab. Furthermore, the CCS1 bands covered all the bands detected by RCS1, which suggests that some CCS1 repeats were distributed together with RCS1. The frequency of CCS1 families was once every 35.8 kb, nearly twice that of RCS1. Fluorescence in situ hybridization （FISH） analysis Indicated that the five BAC clones containing RCS1 and CCS1 sequences all detected signals at the centromerlc regions in hexaplold wheat, but the signal intensities on the A-genome chromosomes were stronger than those on the B- and/or Dgenome chromosomes. The FISH analysis among nine Triticeae cereals indicated that there were A-genomespecific （or rich） sequences dispersing on chromosome arms in the BAC clone TbBACS. In addition, at the interphase cells, the centromeres of diploid species usually clustered at one pole and formed a ring-like allocation In the period before metaphase.
文摘A bacterial artificial chromosome library has been constructed for Triticum boeoticum Boiss (A bA b) using the bacterial artificial chromosome (BAC) vector pECBAC1. The library consists of about 170 000 clones. A random sampling analysis of 200 BAC clones indicates that the average insert size is 104 kb. Based on the genome size of T. boeoticum, the library is about three times as large as T. boeoticum haploid genome (5 600 Mb). Screening the BAC library with cpDNA sequence psbA gene and mtDNA sequence atp6 gene as probe shows that contamination of the library with chloroplast and mitochondrial clones is less than 1%. The library will be a useful platform in gene clone and genomic research of wheat.
文摘Although Iran is a main center of distribution of wild wheats, but little information is available regarding genetic variation in wild wheat relatives from this country (Tabatabaei and Massoumi, 2001). The habitats of
