Animal models provide useful tools for exploring the genetic basis of morphological,
physiological and behavioral phenotypes. Cave-adapted species are particularly powerful
models for a broad array of phenotypic changes with evolutionary, developmental
and clinical relevance. Here, we explored the genetic underpinnings of previously
characterized differences in locomotor activity patterns between the surface-dwelling
and Pachón cave-dwelling populations of Astyanax mexicanus. We identified multiple
novel QTL underlying patterns in overall levels of activity (velocity), as well as spatial
tank use (time spent near the top or bottom of the tank). Further, we demonstrated that
different regions of the genome mediate distinct patterns in velocity and tank usage.
We interrogated eight genomic intervals underlying these activity QTL distributed
across six linkage groups. In addition, we employed transcriptomic data and draft
genomic resources to generate and evaluate a list of 36 potential candidate genes.
Interestingly, our data support the candidacy of a number of genes, but do not suggest
that differences in the patterns of behavior observed here are the result of alterations to
certain candidate genes described in other species (e.g., teleost multiple tissue opsins,
melanopsins or members of the core circadian clockwork). This study expands our
knowledge of the genetic architecture underlying activity differences in surface and
cavefish. Future studies will help define the role of specific genes in shaping complex
behavioral phenotypes in Astyanax and other vertebrate taxa.