Table 4 lists additional information related to peptide sequences and calculated sequence identities. Additional genes (increase in gene number, compared with humans) show peptide divergence of as little as 0.4 per cent (zebrafish aldh2.2 and aldh2.3) and as much as 64.9 per cent (zebrafish aldh3a2.1 and aldh3a2.2). In most cases, gene duplications have similar sizes, are often nearby on the same chromosome (Chr) and show some degree of divergence (ie 70-95 per cent AA identity). Genes that have portions of the gene copied with no AA divergence include: cow ALDH1A3P1 (127 of 537 AAs), zebrafish aldh5a1.2 (404 of 514 AAs) and zebrafish aldh18a1.2 (782 of 782 AAs). Zebrafish aldh3a2.3 (169 of 514 AAs) represents a shortened copy which shows minor divergence (98.4 per cent identity). Ka/Ks ratios were calculated for all gene duplications. A value of < 1.0 indicates selective pressure to conserve the gene and suggests that it plays a functional role. All duplications were found to have a score of < 1.0, except macaque ALDH7A1P5 (to be discussed below).
