Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50677
標題: Molecular organization of large fragments in the maize B chromosome: Indication of a novel repeat
作者: Cheng, Y.M.
鄭雅銘
Lin, B.Y.
關鍵字: repeated sequences
brachycome-dichromosomatica
centromeric sequence
gap repair
family
identification
transposon
element
origin
期刊/報告no:: Genetics, Volume 166, Issue 4, Page(s) 1947-1961.
摘要: The supernumerary B chromosome has no apparent effects on plant. growth, and its molecular makeup is difficult to unravel, due to its high homology to the normal complement, which prevents conventional cloning. This difficulty was overcome previously by microdissecting the B chromosome under the microscope to result in 19 B clones, one of which is B specific and highly repetitive, dispersing over one-third of the B long arm and most regions of the centromeric knob. To gain insights into the molecular structure of the B chromosome, this sequence was used to screen a genomic library constructed from W22 carrying 16 B's. Five clones ( > 10 kb each) were isolated, and all were repetitive, showing homology with A chromosomes in Southern and FISH analyses. Two of them were further characterized and sequenced. Each is composed of several restriction fragments with variable degrees of repetitiveness. Some of these are B specific and others have variable degrees of homology with the A chromosomes. The order of each characteristic group is not contiguous; they intersperse within those of other groups. Sequence analysis reveals that their sequences (similar to26 kb) have no homology with any published gene other than sequences of transposable elements (retrotransposons and MITEs) and the B as well as the A centromeres. We uncovered a 1.6-kb CL-repeat sequence, seven units of which were present in the two clones in defective forms. Those repeats mostly arrange in tandem array ill the B chromosome. Moreover, we detected transposition of a retrotransposon and a MITE element involved in the genesis of these two sequences.
URI: http://hdl.handle.net/11455/50677
ISSN: 0016-6731
文章連結: http://dx.doi.org/10.1534/genetics.166.4.1947
Appears in Collections:農藝學系

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.