Amino acid and nucleotide recurrence in aligned sequences: synonymous substitution patterns in association with global and local base compositions.

ABSTRACT: The tendency for repetitiveness of nucleotides in DNA sequences has been reported for a variety of organisms. We show that the tendency for repetitive use of amino acids is widespread and is observed even for segments conserved between human and Drosophila melanogaster at the level of >50% amino acid identity. This indicates that repetitiveness influences not only the weakly constrained segments but also those sequence segments conserved among phyla. Not only glutamine (Q) but also many of the 20 amino acids show a comparable level of repetitiveness. Repetitiveness in bases at codon position 3 is stronger for human than for D.melanogaster, whereas local repetitiveness in intron sequences is similar between the two organisms. While genes for immune system-specific proteins, but not ancient

SUBMITTER: Nishizawa M 

PROVIDER: S-EPMC110763 | biostudies-literature | 2000 Oct

REPOSITORIES: biostudies-literature