Abstract Detail

Molecular Ecology

Szukala, Aglaia [1], Frajman, Bozo [2], Schönswetter, Peter [2], Paun, Ovidiu [3].

An integrative perspective of adaptation to different altitudes in the Alps.

Independent instances of divergence with similar phenotypic outcome (parallel evolution) provide natural evolutionary replicates to investigate the adaptation to new ecological niches. The alpine plant Heliosperma pusillum Waldst. & Kit. comprises two ecotypes (low vs. high elevation) that maintain different phenotypes (trichomy vs. glabrous) when grown under the same conditions for several generations. We show that the low-elevation ecotype diverged from the high-elevation ecotype multiple times independently by comparing alternative demographic scenarios using the site frequency spectrum as summary statistic. To understand the genetic basis of adaptation to different altitudes, we performed differential expression analyses of plants grown in a common garden and reciprocal transplantations. Our results show that the hairy low-elevation ecotype adapted to poor light and dry conditions by upregulating genes involved in trichomes formation and response to water deprivation, while several genes involved in light harvesting and photosynthesis are downregulated. Despite the parallelism found at the functional level, we detect very low overlap of genes differentially expressed between ecotypes across origins and treatments, indicating that changes in different genes and pathway components led to similar outcomes independently. Reciprocal transplantations show a clear home-site advantage and that the low-elevation ecotype bears higher plasticity of gene expression. Polygenic traits appear key to parallel evolution, by providing the substrate to reproducible outcomes in independent divergence events. Finally, higher phenotypic plasticity might facilitate the adaptation to drier and warmer environments in this plant system.

1 - University of Vienna, Botany and Biodiversity Research, Vienna, 1030, Austria
2 - University of Innsbruck, Austria
3 - University Of Vienna , Department Of Botany And Biodiversity Research, Rennweg 14, Vienna, A-1030, Austria

Keywords:
parallel evolution
Alps
transcriptomics
phenotypic plasticity
polygenic adaptation.

Presentation Type: Oral Paper
Session: MOL1, Molecular Ecology
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 1:00 PM
Number: MOL1003
Abstract ID:269
Candidate for Awards:None