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Reverse polarization in amino acid and nucleotide substitution patterns between human-mouse orthologs of two compositional extrema

Metadata of CSIR Papers


Field	Value

Title	Reverse polarization in amino acid and nucleotide substitution patterns between human-mouse orthologs of two compositional extrema

Creator	Bag, SK Paul, S Ghosh, S Dutta, C

Subject	Genetics & Heredity

Description	Genome-wide analysis of sequence divergence patterns in 12 024 human-mouse orthologous pairs reveals, for the first time, that the trends in nucleotide and amino acid substitutions in orthologs of high and low GC composition are highly asymmetric and polarized to opposite directions. The entire dataset has been divided into three groups on the basis of the GC content at third codon sites of human genes: high, medium, and low. High-GC orthologs exhibit significant bias in favor of the replacements, Thr -> Ala, Ser -> Ala, Val -> Ala, Lys -> Arg, Asn -> Ser, Ile -> Val etc., from mouse to human, whereas in low-GC orthologs, the reverse trends prevail. In general, in the high-GC group, residues encoded by A/U-rich codons of mouse proteins tend to be replaced by the residues encoded by relatively G/C-rich codons in their human orthologs, whereas the opposite trend is observed among the low-GC orthologous pairs. The medium-GC group shares some trends with high-GC group and some with low-GC group. The only significant trend common in all groups of orthologs, irrespective of their GC bias, is (Asp)(Mouse) -> (Glu)(Human) replacement. At the nucleotide level, high-GC orthologs have undergone a large excess of (A/T)(Mouse) -> (G/C)(Human) substitutions over (G/C)(Mouse) -> (A/T)(Human) at each codon position, whereas for low-GC orthologs, the reverse is true.

Publisher	OXFORD UNIV PRESSOXFORDGREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND

Date	2011-09-20T12:12:26Z 2011-09-20T12:12:26Z 2007

Type	Article

Identifier	DNA RESEARCH 1340-2838 http://hdl.handle.net/123456789/14274

Language	English