PT  - JOURNAL ARTICLE
AU  - Andrea Desiderato
AU  - Marcos Barbeitos
AU  - Clément Gilbert
AU  - Jean-Luc Da Lage
TI  - Horizontal transfer and gene loss shaped the evolution of alpha-amylases in bilaterians
AID  - 10.1101/670273
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 670273
4099  - http://biorxiv.org/content/early/2019/06/17/670273.short
4100  - http://biorxiv.org/content/early/2019/06/17/670273.full
AB  - The subfamily GH13_1 of alpha-amylases is typical of Fungi, but it also includes some unicellular eukaryotes (e.g. Amoebozoa, choanoflagellates) and non-bilaterian Metazoa. Conversely, since a previous study in 2007, all Bilateria were considered to harbor only alpha-amylases supposedly inherited by horizontal transfer from a proteobacterium and classified in the subfamilies GH13_15 and 24, which were therefore commonly called bilaterian alpha-amylases. The taxonomic scope of Eukaryota genomes in databases has been greatly increased ever since 2007. We have surveyed GH13_1 sequences in recent data from non-bilaterian animals and unicellular eukaryotes. We found a number of those sequences in Anthozoa (Cnidaria) and in sponges, confirming the previous observations, but none in Ctenophora. Most surprisingly, such fungal (also called Dictyo-type) amylases were also consistently retrieved in a limited number of bilaterian phyla: hemichordates (deuterostomes), brachiopods, some molluscs and annelids (protostomes). We discuss evolutionary hypotheses for these findings, namely, the retention of the ancestral gene in those phyla only and/or horizontal transfers from non-bilaterian donors.