Evolution of aldehyde dehydrogenase genes and proteins in diploid and allotetraploid Xenopus frog species

At least 19 human aldehyde dehydrogenase (ALDH) genes and enzymes have been studied among vertebrate organisms. BLAT and BLAST analyses were undertaken of Xenopus tropicalis (western clawed frog) and Xenopus laevis (African clawed frog) genomes which are related diploid (N = 20) and allotetraploid (N = 36) species, respectively. The corresponding ALDH genes and proteins within these Xenopus genomes were identified and studied. Evidence is presented for tetraploid copies of 10 Xenopus laevis ALDH genes, whereas another 7 identified ALDH genes were diploid in nature. Xenopus laevis and Xenopus tropicalis ALDH amino acid sequences were highly homologous with the human enzymes, with the exception of the mitochondrial signal peptide sequences. Amino acids performing catalytic and structural roles were conserved and identified based on previous reports of 3D structures for the corresponding mammalian enzymes.

Automated summary

The study identified tetraploid copies of 10 Xenopus laevis ALDH genes, while another 7 ALDH genes were diploid in nature. The ALDH amino acid sequences of Xenopus laevis and Xenopus tropicalis were highly homologous with human enzymes, except for mitochondrial signal peptide sequences. Amino acids responsible for catalytic and structural roles were conserved and identified based on previous reports of 3D structures of corresponding mammalian enzymes.