Assessments of DNA inhomogeneities in yeast chromosome III

• Published in: Nucleic acids research 1993-02, Vol.21 (3), p.703-711
• Main Authors: Karlin, S, Blaisdell, B.E, Sapolsky, R.J, Cardon, L, Burge, C
• Format: Article
• Language: English
• Subjects: autonomously replicating sequences; base composition; Biological and medical sciences; chemical composition; Chromosome Mapping; chromosomes; Chromosomes, Fungal; cytosine; DNA, Fungal - genetics; Fundamental and applied biological sciences. Psychology; genes; Genes, Fungal; Genes. Genome; Genetic Variation; guanosine; Humans; Molecular and cellular biology; Molecular genetics; nucleotide sequences; Oligodeoxyribonucleotides; Poly A; Poly dA-dT; Poly T; repetitive sequences; Repetitive Sequences, Nucleic Acid; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; statistical analysis; tandem dna repeats; terminal repeat sequences
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/21.3.703

With the sequencing of the first complete eukaryotic chromosome, III of yeast (YCIII) of length 315 kb, several types of questions concerning chromosomal organization and the heterogeneity of eukaryotic DNA sequences can be approached. We have undertaken extensive analysis of YCIII with the goals of: (1) discerning patterns and anomalies in the occurrences of short oligonucleotides; (2) characterizing the nature and locations of significant direct and inverted repeats; (3) delimiting regions unusually rich in particular base types (e.g., G + C, purines); and (4) analyzing the distributions of markers of interest, e.g., delta elements, ARS (autonomous replicating sequences), special oligonucleotides, close repeats and close dyad pairings, and gene sequences. YCIII reveals several distinctive sequence features, including: (I) a relative abundance of significant local and global repeats highlighting five genes containing substantial close or tandem DNA repeats; (II) an anomalous distribution of delta elements involving two clusters and a long gap; (III) a significantly even distribution of ARS; (IV) a relative increase in the frequency of T runs and AT iterations downstream of genes and A runs upstream of genes; and (V) two regions of complex repetitive sequences and anomalous DNA composition, 29000-31000 and 291000-295000, the latter centered at the HMRa locus. Interpretations of these findings for chromosomal organization and implications for regulation of gene expression are discussed.