TY - JOUR

T1 - From tides to nucleotides

T2 - Genomic signatures of adaptation to environmental heterogeneity in barnacles

AU - Nunez, Joaquin C. B.

AU - Rong, Stephen

AU - Ferranti, David A.

AU - Damian-Serrano, Alejandro

AU - Neil, Kimberly B.

AU - Glenner, Henrik

AU - Elyanow, Rebecca G.

AU - Brown, Bianca R. P.

AU - Alm Rosenblad, Magnus

AU - Blomberg, Anders

AU - Johannesson, Kerstin

AU - Rand, David M.

N1 - Publisher Copyright: © 2021 The Authors. Molecular Ecology published by John Wiley & Sons Ltd

PY - 2021

Y1 - 2021

N2 - The northern acorn barnacle (Semibalanus balanoides) is a robust system to study the genetic basis of adaptations to highly heterogeneous environments. Adult barnacles may be exposed to highly dissimilar levels of thermal stress depending on where they settle in the intertidal (i.e., closer to the upper or lower tidal boundary). For instance, barnacles near the upper tidal limit experience episodic summer temperatures above recorded heat coma levels. This differential stress at the microhabitat level is also dependent on the aspect of sun exposure. In the present study, we used pool-seq approaches to conduct a genome wide screen for loci responding to intertidal zonation across the North Atlantic basin (Maine, Rhode Island, and Norway). Our analysis discovered 382 genomic regions containing SNPs which are consistently zonated (i.e., SNPs whose frequencies vary depending on their position in the rocky intertidal) across all surveyed habitats. Notably, most zonated SNPs are young and private to the North Atlantic. These regions show high levels of genetic differentiation across ecologically extreme microhabitats concomitant with elevated levels of genetic variation and Tajima's D, suggesting the action of non-neutral processes. Overall, these findings support the hypothesis that spatially heterogeneous selection is a general and repeatable feature for this species, and that natural selection can maintain functional genetic variation in heterogeneous environments.

AB - The northern acorn barnacle (Semibalanus balanoides) is a robust system to study the genetic basis of adaptations to highly heterogeneous environments. Adult barnacles may be exposed to highly dissimilar levels of thermal stress depending on where they settle in the intertidal (i.e., closer to the upper or lower tidal boundary). For instance, barnacles near the upper tidal limit experience episodic summer temperatures above recorded heat coma levels. This differential stress at the microhabitat level is also dependent on the aspect of sun exposure. In the present study, we used pool-seq approaches to conduct a genome wide screen for loci responding to intertidal zonation across the North Atlantic basin (Maine, Rhode Island, and Norway). Our analysis discovered 382 genomic regions containing SNPs which are consistently zonated (i.e., SNPs whose frequencies vary depending on their position in the rocky intertidal) across all surveyed habitats. Notably, most zonated SNPs are young and private to the North Atlantic. These regions show high levels of genetic differentiation across ecologically extreme microhabitats concomitant with elevated levels of genetic variation and Tajima's D, suggesting the action of non-neutral processes. Overall, these findings support the hypothesis that spatially heterogeneous selection is a general and repeatable feature for this species, and that natural selection can maintain functional genetic variation in heterogeneous environments.

KW - balancing selection

KW - barnacles

KW - ecological genomics

KW - ecological load

KW - intertidal

KW - Semibalanus balanoides

KW - zonation

U2 - 10.1111/mec.15949

DO - 10.1111/mec.15949

M3 - Journal article

C2 - 33960035

AN - SCOPUS:85106207487

VL - 30

SP - 6417

EP - 6433

JO - Molecular Ecology

JF - Molecular Ecology

SN - 0962-1083

IS - 23

ER -