1993 Fiscal Year Final Research Report Summary
Chromosome bands and giant G+C% mosaic structures of higher vertebrates genome
| Project/Area Number |
04640598
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
遺伝学
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| Research Institution | National Institute of Genetics |
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Principal Investigator |
IKEMURA Toshimichi National Institute of Genetics, Dept.of Population Genetics, Professor, 集団遺伝研究系, 教授 (50025475)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Ken-ichi National Institute of Genetics, Dept.of Population Genetics, Assistant Professor, 集団遺伝研究系, 助手 (30202328)
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| Project Period (FY) |
1992 – 1993
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| Keywords | MHC locus / Chromosome bands / GC content / Codon usage / Notch gene / Extracellular matrix protein / Homeobox gene / Pseudoautosomal boundary |
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| Research Abstract |
We found human MHC (HLA) is a typical example of long-range G+C% mosaic structures (1-3). HLA is composed of classes I, III and II from telomere to centromere and contiguous classes I and III (a total of 3 Mb) correspond to evidently GC-rich domain and class II (1 Mb), to the domain with reduced G+C%. To precisely locate and characterize boundary of the Mb-level G+C% mosaic domains, cosmid walking from the most centromeric class III gene TN-X to class II and that from the most telomeric DRA to class III were conducted and contiguous clones totally covering the domain boundary were obtained bridging classes II and III.A sharp G+C% transition of the long-range G+C% mosaic domains corresponding to L <-> Hisochores (and presumably G <-> R bands) could be precisely defined, and the following organization was revealed.
(L isochore) PAB-like - Dense L1 cluster - Dense Alu cluster (H isochore)
Human sex chromosomes are divided into sex-specific and pseudoautosomal regions (PAR). Existence of PAR was deduced from observations of male meiosis, when sex chromosomes pair and form chiasmata, interface between sex-specific and PAR is the pseudoautosomal boundary (PAB, about 400 nt) that is the centromeric limit to recombination in PAR.Interestingly, complete form of PAB-like sequence (about 80% nucleotide identity) was found near the sharp G+C% transition point in HLA.A large number of PAB-like sequences could be detected in the human genome by hybridization using this HLA probe and the complete form of PAB-like sequence (about 600 nt) could be defined by sequencing several of them. (1) J.Mol.Biol.203,1 (1988). (2) Genomics 8,207 (1990). (3) HLA1991 (Oxford Univ.Press) vol.2, 125.
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Research Products
(12 results)
