title: Molecular phenotyping of maternally mediated parallel adaptive divergence within Rana arvalis and Rana temporaria.
abstract: When similar selection acts on the same traits in multiple species or populations, parallel evolution can result in similar phenotypic changes, yet the underlying molecular architecture of parallel phenotypic divergence can be variable. Maternal effects can influence evolution at ecological timescales and facilitate local adaptation, but their contribution to parallel adaptive divergence is unclear. In this study, we (i) tested for variation in embryonic acid tolerance in a common garden experiment and (ii) used molecular phenotyping of egg coats to investigate the molecular basis of maternally mediated parallel adaptive divergence in two amphibian species (Rana arvalis and Rana temporaria). Our results on three R. arvalis and two R. temporaria populations show that adaptive divergence in embryonic acid tolerance is mediated via maternally derived egg coats in both species. We find extensive polymorphism in egg jelly coat glycoproteins within both species and that acid-tolerant clutches have more negatively charged egg jelly - indicating that the glycosylation status of the jelly coat proteins is under divergent selection in acidified environments, likely due to its impact on jelly water balance. Overall, these data provide evidence for parallel mechanisms of adaptive divergence in two species. Our study highlights the importance of studying intraspecific molecular variation in egg coats and, specifically, their glycoproteins, to increase understanding of underlying forces maintaining variation in jelly coats.
authors.affiliation: Department of Aquatic Ecology, Eawag, Duebendorf, 8600, Switzerland. longfei.shu@wustl.edu.|Institute of Integrative Biology, ETH Zürich, Zürich, 8092, Switzerland. longfei.shu@wustl.edu.
authors.forename: Longfei
authors.initials: L
authors.lastname: Shu
authors.affiliation: Animal Ecology/Department of Ecology and Genetics, Evolutionary Biology Center, Uppsala University, Uppsala, 75236, Sweden.
authors.forename: Anssi
authors.initials: A
authors.lastname: Laurila
authors.affiliation: Department of Environmental Toxicology, Eawag, Duebendorf, 8600, Switzerland.|Department of Environmental Systems Science, ETH Zürich, Zürich, 8092, Switzerland.
authors.forename: Marc J-F
authors.initials: MJ
authors.lastname: Suter
authors.affiliation: Department of Aquatic Ecology, Eawag, Duebendorf, 8600, Switzerland.|Institute of Integrative Biology, ETH Zürich, Zürich, 8092, Switzerland.
authors.forename: Katja
authors.initials: K
authors.lastname: Räsänen
mesh_terms: D000143:Acids / Q000737:chemistry; D000222:Adaptation, Physiological / Q000235:genetics*; D029845:Amphibian Proteins / Q000235:genetics*; D000818:Animals; D004527:Egg Proteins / Q000235:genetics*; D004777:Environment; D005260:Female; D010063:Ovum; D010641:Phenotype; D011896:Rana temporaria / Q000235:genetics*; D011898:Ranidae / Q000235:genetics*; D013548:Sweden
chemical_list: D000143:Acids; D029845:Amphibian Proteins; D004527:Egg Proteins
keywords: SDS-PAGE; acid tolerance; amphibians; glycoproteins; jelly coats; maternal effects; molecular phenotyping; parallel evolution; zeta potential