Duplicated Paralogous Genes Subject to Positive Selection in the Genome of Trypanosoma brucei

• Published in: PloS one Vol. 3; no. 5; p. e2295
• Main Authors: Emes, Richard D., Yang, Ziheng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.05.2008; Public Library of Science (PLoS)
• Subjects: Accuracy; Acids; Adaptive control; Adenylyl Cyclases - genetics; Amino acid substitution; Amino Acid Transport Systems - genetics; Amino acids; Animals; Antigens; Biological evolution; Biology; Codons; Drug resistance; Evolution; Evolution & development; Evolution, Molecular; Evolutionary Biology; Evolutionary Biology/Evolutionary and Comparative Genetics; Evolutionary Biology/Genomics; Evolutionary genetics; Gene Duplication; Genes; Genetic aspects; Genetics and Genomics/Comparative Genomics; Genetics and Genomics/Medical Genetics; Genome, Protozoan; Genomes; Genomics; Immune system; Infectious Diseases/Neglected Tropical Diseases; Infectious Diseases/Protozoal Infections; Infectious Diseases/Tropical and Travel-Associated Diseases; Insects; Life cycle engineering; Life cycles; Ligands; Mammals; Membrane Glycoproteins - genetics; Natural selection; Nucleoside Transport Proteins - genetics; Parasites; Phylogenetics; Positive selection; Proteins; Protozoan Proteins - genetics; Reproduction (copying); Selection, Genetic; Statistical methods; Substrates; Surface antigens; Trypanosoma brucei; Trypanosoma brucei brucei - genetics
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0002295

Whole genome studies have highlighted duplicated genes as important substrates for adaptive evolution. We have investigated adaptive evolution in this class of genes in the human parasite Trypanosoma brucei, as indicated by the ratio of non-synonymous (amino-acid changing) to synonymous (amino acid retaining) nucleotide substitution rates. We have identified duplicated genes that are most rapidly evolving in this important human parasite. This is the first attempt to investigate adaptive evolution in this species at the codon level. We identify 109 genes within 23 clusters of paralogous gene expansions to be subject to positive selection. Genes identified include surface antigens in both the mammalian and insect host life cycle stage suggesting that competitive interaction is not solely with the adaptive immune system of the mammalian host. Also surface transporters related to drug resistance and genes related to developmental progression are detected. We discuss how adaptive evolution of these genes may highlight lineage specific processes essential for parasite survival. We also discuss the implications of adaptive evolution of these targets for parasite biology and control.