首页|Mitochondrial phylogeography and molecular evolution of the rhodopsin visual pigment in troglobitic populations of Astyanax mexicanus(De Filippi,1853)

Mitochondrial phylogeography and molecular evolution of the rhodopsin visual pigment in troglobitic populations of Astyanax mexicanus(De Filippi,1853)

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Cave-adapted animals provide a unique opportunity to study the evolutionary mechanisms underlying phenotypic,metabolic,behavioral,and genetic evolution in response to cave environments.The Mexican tetra(Astyanax mexicanus)is considered a unique model system as it shows both surface and cave-dwelling morphs.To date,at least 33 different cave populations have been identified,with phylogenetic studies suggesting an origin from at least two independent surface lineages,thereby providing a unique opportunity to study parallel evolution.In the present study,we carried out the most exhaustive phylogeographic study of A.mexicanus to date,including cave and surface localities,using two mitochondrial markers(cytochrome b(cyt b)and cytochrome c oxidase subunit Ⅰ(COI))and nuclear rhodopsin visual pigment(rho).Additionally,we inferred the molecular evolution of rho within the two contrasting environments(cave and surface)and across three geographic regions(Sierra de El Abra,Sierra de Guatemala,and Micos).In total,267 individuals were sequenced for the two mitochondrial fragments and 268 individuals were sequenced for the rho visual pigment from 22 cave and 46 surface populations.Phylogeographic results based on the mitochondrial data supported the two-lineage hypothesis,except for the Pachón and Chica caves,whose introgression has been largely documented.The Sierra de El Abra region depicted the largest genetic diversity,followed by the Sierra de Guatemala region.Regarding the phylogeographic patterns of rho,we recovered exclusive haplogroups for the Sierra de El Abra(Haplogroup Ⅰ)and Sierra de Guatemala regions(Haplogroup Ⅳ).Moreover,a 544 bp deletion in the rho gene was observed in the Escondido cave population from Sierra de Guatemala,reducing the protein from seven to three intramembrane domains.This change may produce a loss-of-function(LOF)but requires further investigation.Regarding nonsynonymous(dN)and synonymous(dS)substitution rates(omega values ω),our results revealed the prevailing influence of purifying selection upon the rho pigment for both cave and surface populations(ω＜1),but relaxation at the El Abra region.Notably,in contrast to the other two regions,we observed an increase in the number of dN mutations for Sierra de El Abra.However,given that a LOF was exclusively identified in the Sierra de Guatemala region,we cannot dismiss the possibility of a pleiotropic effect on the Rho protein.

Visual pigmentsSelectionCavefishVision lossLoss of function

Marco A.A.Gardu?o-Sánchez、Vladimir de Jesus-Bonilla、Silvia Perea、Ramses Miranda-Gamboa、Andrea Herrera-García、Mauricio de la Maza Benignos、Claudia Patricia Ornelas-García

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Colección Nacional de Peces,Departamento de Zoología,Instituto de Biología,Universidad Nacional Autónoma de México,Ciudad de México,C.P.04510,México

Posgrado en Ciencias Biológicas,Colección Nacional de Peces,Departamento de Zoología,Instituto de Biología,Universidad Nacional Autónoma de México,Ciudad de México,C.P.04510,México

Licenciatura en Ciencias Forenses,Facultad de Medicina,Universidad Nacional Autónoma de México,Ciudad Universitaria,Coyoacán,México City,C.P.04510,México

Instituto de Energías Renovables,Universidad Nacional Autónoma de México,Temixco,Morelos C.P.62580,Mexico

Facultad de Ciencias Biológicas,Universidad Autónoma de Nuevo León,Ciudad Universitaria,San Nicolás de los Garza,Nuevo León,C.P.66450,México

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Fronteras de la Ciencia-CONACyT and Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica(PAPIIT),UNAMFronteras de la Ciencia-CONACyT and Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica(PAPIIT),UNAM

191986IN212419

2023

10.24272/j.issn.2095-8137.2022.437

动物学研究
中国科学院昆明动物研究所 中国动物学会

动物学研究

CSTPCDCSCD
影响因子：0.582
ISSN：0254-5853
年,卷(期)：2023.44(4)
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