Meeting Abstract
The ability of organisms to co-opt genes for new purposes, or to neofunctionalize gene duplicates, is a major focus of evolutionary biology and comparative genomics. However, relatively less attention has been paid to the role of gene loss as a driver of adaptive shifts in organismal biology. Loss of function evolution has been shown repeatedly in microbial species living in close relationships with host taxa, and in the host taxa themselves. Poriferans, with their diverse microbiome communities, are excellent candidates for horizontal gene transfer and gene loss that could result in degeneracy of morphological traits and loss of gene families. Here we develop a catalogue of reference-based gene presence/absence from estimates of orthology across a selection of metazoan genome-scale datasets. We then apply a stochastic model for binary trait evolution conditioned on gene presence/absence data across lineages and gene categories. Using this model, we find evidence of widespread gene loss in sponges compared to other lineages, and our findings are consistent with the hypothesis that extant sponges represent a degeneration of ancestral complexity.
