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Current Genomics

Editor-in-Chief

ISSN (Print): 1389-2029
ISSN (Online): 1875-5488

Replication-Associated Mutational Pressure (RMP) Governs Strand-Biased Compositional Asymmetry (SCA) and Gene Organization in Animal Mitochondrial Genomes

Author(s): Qiang Lin, Peng Cui, Feng Ding, Songnian Hu and Jun Yu

Volume 13, Issue 1, 2012

Page: [28 - 36] Pages: 9

DOI: 10.2174/138920212799034811

Price: $65

Abstract

The nucleotide composition of the light (L-) and heavy (H-) strands of animal mitochondrial genomes is known to exhibit strand-biased compositional asymmetry (SCA). One of the possibilities is the existence of a replicationassociated mutational pressure (RMP) that may introduce characteristic nucleotide changes among mitochondrial genomes of different animal lineages. Here, we discuss the influence of RMP on nucleotide and amino acid compositions as well as gene organization. Among animal mitochondrial genomes, RMP may represent the major force that compels the evolution of mitochondrial protein-coding genes, coupled with other process-based selective pressures, such as on components of translation machinery- tRNAs and their anticodons. Through comparative analyses of sequenced mitochondrial genomes among diverse animal lineages and literature reviews, we suggest a strong RMP effect, observed among invertebrate mitochondrial genes as compared to those of vertebrates, that is either a result of positive selection on the invertebrate or a relaxed selective pressure on the vertebrate mitochondrial genes.

Keywords: Function-based selection, mitochondrion genome, replication-associated mutational pressure, strand-biased compositional asymmetry, Gene Organization, PROTEIN-CODING SEQUENCES, GC skew, AT skew, tRNAs, isochores


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