The effect of expression levels on codon usage in Plasmodium falciparum.
The usage of alternative synonymous codons in the completely sequenced, extremely A+T-rich parasite Plasmodium falciparum was studied. Confirming previous studies obtained with less than 3% of the total genes recently described, we found that A- and U-ending triplets predominate but translational selection increases the frequency of a subset of codons in highly expressed genes. However, some new results come from the analysis of the complete sequence. First, there is more variation in GC3 than previously described; second, the effect of natural selection acting at the level of translation has been analysed with real expression data at 4 different stages and third, we found that highly expressed proteins increment the frequency of energetically less expensive amino acids. The implications of these results are discussed.
Peixoto
L
L
Laboratorio de Organización Evolución del Genoma, Facultad de Ciencias, Iguá 4225, Montevideo 11400, Uruguay.
Fernández
V
V
Musto
H
H
D000818:Animals; D001482:Base Composition; D003062:Codon; D005786:Gene Expression Regulation / Q000235:genetics*; D014644:Genetic Variation; D018503:Genome, Protozoan; D010963:Plasmodium falciparum / Q000235:genetics*; D012641:Selection, Genetic
D003062:Codon