Conference Paper
Molecular evolution of rhodopsin gene in Astyanax mexicanus (De Filippi, 1853)
Garduño-Sánchez, M.A.A. and Ornelas-García, C.P.
Record Number:
4282
Year:
2019
Journal:
AIM 2019
Pages:
34
Abstract:
Previous studies have shown that eyes loss under cave habitats, could be affected by the loss of
gene function, however, in Astyanax mexicanus little is known about the evolution of visual-related
genes. In order to evaluate the mechanisms underlaying the evolution of visual-related genes, we
characterized the evolutionary history of the visual pigment rhodopsin (rho), an intermembrane
receptor associated with photoreception in low light conditions, under contrasting environments
(caves vs. surface), and compared it with a genealogy of two mitochondrial genes (mt-cyb and
mt-cox1). We surveyed 20 cave and 49 surface populations for Sierra del Abra, Sierra de
Guatemala and Micos regions. We carried out a Bayesian phylogenetic reconstruction (MrBayes
v. 3.2.6) and haplotype network using PopArt v1.7. Additionally, we assessed the divergence
between synonymous (ds) and non-synonymous substitutions (dn) by codon, across lineages and
geographic systems in SNAP v.2.1.1. A 3D protein modeling of the different haplotypes recovered
for rho gene was constructed in Phyre2 v.2. Our results show a specific haplotype distribution
with a clear geographic congruence, supporting two haplogroups mainly corresponding to
lineages (i.e., “new” vs. “old”). We obtained a higher frequency of dn substitutions in the old
lineage compared to the new lineage. The 3D protein structure for rho gene showed three
domains, instead of seven, for Escondido cave population, in addition, amino acid polymorphisms
differences between lineages and environments were detected. This study supports rho geneloss
associated with visual-loss, in 1 of 20 cavefish populations analyzed.
Times Cited:
1
Conference Name:
Astyanax Interrnational Meeting
Relevent Species: