Codon usage in the siliceous sponge Geodia cydonium: highly expressed genes in the simplest multicellular animals prefer C- and G-ending codons

2001

Among a sample of 39 Geodia cydonium (Demospongiae, Porifera) genes, with an average Gh+hC content of 51.2%, extensive structural heterogeneity and considerable variations in synonymous codon usage were found. The G + C content of coding sequences and G + C content at silent codon positions (GC3S) varied from 42.4 to 59.2% and from 35.6 to 76.5%, respectively. Correspondence analysis of 39 genes revealed that putative highly expressed genes preferentially use a limited subset of codons, which were therefore defined as preferred codons in G. cydonium. A total of 22 preferred codons for 18 amino acids with synonyms in codons were identified and they all (with one exception) end with C or G. A…