TABLE 6.
Intraspecific and interspecific comparisons of preferred codons in PF and in non-PF exons from D. melanogaster, D. pseudoobscura, and D. virilis
| A. Intraspecific comparisons | ||
|---|---|---|
| Same codons preferred | Different codons preferred | |
| Six-codon families (ARG, LEU, SER) | 0 | 9 |
| Four- or three-codon families (ALA, GLY, ILE, PRO THR, VAL) | 1 | 17 |
| Two-codon families (ASN, ASP, CYS, GLN, GLU, HIS, LYS, PHE, TYR) | 10 | 10 |
| Total | 11 | 36 |
| B. Interspecific comparisons | |||
|---|---|---|---|
| Same preferred codon in the compared species | Different preferred codon(s) in the compared species | ||
| Six-, four- and three-codon families | Non-PF exons | 4 | 5 |
| PF exonsa | 0 | 9 | |
| Two-codon families | Non-PF exons | 7 | 2 |
| PF exonsa | 5 | 3 | |
a
For the PF exon, only two species could be compared in the two-codon families for ASN, HIS, PHE, and TYR, and none could be compared for CYS.