A comparison of GC content and the proportion of Alu/KpnI-repetitive sequences in a single dark- and light-band region from a human chromosome

• Published in: Genomics (San Diego, Calif.) Vol. 20; no. 2; pp. 243 - 248
• Main Authors: YOSHIURA, K.-I, KUBOTA, T, SOEJIMA, H, TAMURA, T, IZUMIKAWA, Y, NIIKAWA, N, JINNO, Y
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier 15.03.1994
• Subjects: Base Composition; Base Sequence; Biological and medical sciences; Blotting, Southern; Chromosome Banding; Chromosomes, Human, Pair 11; Cloning, Molecular; Cosmids; Cytogenetics; Cytosine - analysis; Deoxyribonucleases, Type II Site-Specific - metabolism; Dinucleoside Phosphates - analysis; DNA; Fundamental and applied biological sciences. Psychology; Gene Library; Genetics of eukaryotes. Biological and molecular evolution; Guanine - analysis; Human; Humans; Molecular Sequence Data; Polymerase Chain Reaction; Repetitive Sequences, Nucleic Acid; Human; High repeated sequence; Genome organization; Alu sequence; Microdissection; GC rich sequence; C11-Chromosome; Cytogenetics; Chromosome DNA; Chromosome banding; Gene library; Molecular cloning
• ISSN: 0888-7543; 1089-8646

To obtain direct evidence for a molecular basis of differentiation between regular Giemsa dark (G)- and light (R)-band regions of human chromosomes, two regions of chromosome 11, q14-q22 (G-band) and q23-q25 (R-band), were microdissected. The DNA fragments were amplified by the linker-primer polymerase chain reaction and cloned into pUC19. Microclones from each library were then compared by colony hybridization with repetitive DNA sequences, by Southern blot hybridization of each microclone to total human genomic DNA and mouse-human hybrid cell DNA containing only human chromosome 11, and by sequencing of unique and Alu-repetitive clones. Among the G-band-derived microclones analyzed, 43.0% were single-copy (unique) sequences and 23.2% contained highly repetitive sequence elements; in the R-band-derived library, 54.2% were unique clones and 20.3% had highly repetitive elements. The G-band library was significantly richer in clones positive for KpnI sequences (4.1% in the G-band library vs 2.8% in the R-band library). No significant difference was found in the proportion of Alu repetitive clones present in the two libraries, but Class IV Alu sequence derivatives were more frequently observed in the R-library than in the G-library. Sequence analysis revealed no significant difference in GC content or in the ratio of CpG sequence to GpC dinucleotide between 30 microclones derived from G-bands and 29 microclones derived from R-bands.