title: Distribution of polypyrimidine . polypurine segments in DNA from diverse organisms.
abstract: Polypyrimidine . polypurine segments are regions of duplex DNA which contain a highly asymmetric distribution of pyrimidine and purine nucleotides. A polypyrimidine in single-stranded DNA can be detected by its ability to form a complex and poly(A, G) which will bind to hydroxyapatite. We tested DNA from a variety of organisms and found that most contained polypyrimidines. From the shape of the curve relating DNA size to percentage bound to hydroxyapatite, we conclude that polypyrimidine . polypurine segments occur widely in DNA from higher organisms, at intervals of 6000--8000 base pairs throughout the majority of the genome. Lower levels occur in DNA from yeast and Drosophila.
mesh_terms: D000818:Animals; D001483:Base Sequence; D004247:DNA; D005260:Female; D006801:Humans; D008297:Male; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D011131:Polyribonucleotides; D011687:Purines / Q000032:analysis*; D011743:Pyrimidines / Q000032:analysis*; D013045:Species Specificity
chemical_list: D011131:Polyribonucleotides; D011687:Purines; D011743:Pyrimidines; D004247:DNA