Enzyme-coding genes as molecular clocks: the molecular evolution of animal alpha-amylases.
We constructed a cDNA library for the beetle, Tribolium castaneum. This library was screened using a cloned amylase gene from Drosophila melanogaster as a molecular probe. Beetle amylase cDNA clones were isolated from this bank, and the nucleotide sequence was obtained for a cDNA clone with a coding capacity for 228 amino acids. Both the nucleotide sequence and predicted amino acid sequence were compared to our recent results for D. melanogaster alpha-amylases, along with published sequences for other alpha-amylases. The results show that animal alpha-amylases are highly conserved over their entire length. A broader comparison, which includes plant and microbial alpha-amylase sequences, indicates that parts of the gene are conserved between prokaryotes, plants, and animals. We discuss the potential importance of this and other enzyme-coding genes for the construction of molecular phylogenies and for the study of the general question of molecular clocks in evolution.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D001517:Coleoptera / Q000201:enzymology / Q000235:genetics; D004247:DNA / Q000235:genetics; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology; D051381:Rats; D013045:Species Specificity; D000516:alpha-Amylases / Q000235:genetics*
D004247:DNA; D000516:alpha-Amylases