PT  - JOURNAL ARTICLE
AU  - Cicconardi Francesco
AU  - Krapf Patrick
AU  - D’Annessa Ilda
AU  - Gamisch Alexander
AU  - Wagner Herbert C
AU  - Nguyen Andrew D
AU  - Economo Evan P
AU  - Mikheyev Alexander S
AU  - Guénard Benoit
AU  - Grabherr Reingard
AU  - Arthofer Wolfgang
AU  - di Marino Daniele
AU  - Steiner Florian M
AU  - Schlick-Steiner Birgit C
TI  - Genomic signature of shifts in selection in a sub-alpine ant and its physiological adaptations
AID  - 10.1101/696948
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 696948
4099  - http://biorxiv.org/content/early/2019/08/14/696948.short
4100  - http://biorxiv.org/content/early/2019/08/14/696948.full
AB  - Adaptation to climate can drive variation in diversification rates and species richness. Understanding how organisms adapt to extreme environments can therefore provide insightful case studies for both evolutionary biology and climate-change biology. Here, we take advantage of the vast diversity of lifestyles in ants to identify genomic signatures of adaptation to extreme habitats such as high altitude. We hypothesised two parallel patterns would occur in a genome adapting to an extreme habitat: i) strong positive selection on genes related to adaptation and, ii) a relaxation of previous purifying selection. We tested this hypothesis by sequencing the high-elevation specialist Tetramorium alpestre and four related species. In support of our hypothesis, we recorded a strong shift of selective forces in T. alpestre. We further disentangled candidate molecular adaptations in both gene expression and protein-coding sequence that were identified by our genome wide analyses. In particular, we demonstrate that T. alpestre has i) a derived level of expression for stv and other heat-shock proteins in chill shock tests, and ii) enzymatic enhancement of Hex-T1, a rate-limiting regulatory enzyme that controls the entry of glucose into the glycolytic pathway. Together, our analyses highlight the adaptive molecular changes that support colonisation of high altitude environments.