# Genetic–environment associations explain genetic differentiation and variation between western and eastern North Pacific rhinoceros auklet (Cerorhinca monocerata) breeding colonies

## TL;DR

This study explores how environmental factors influence genetic differences in rhinoceros auklet populations across the North Pacific.

## Contribution

The study is the first to quantify genetic-environment associations in rhinoceros auklets, revealing local adaptation between western and eastern Pacific populations.

## Key findings

- 262 candidate adaptive loci were identified, explaining 3.0% of genetic variation between western and eastern Pacific populations.
- Genetic variation was more strongly associated with pH and current velocity than sea surface temperature.
- Isolation-by-distance patterns were observed within western and eastern Pacific populations.

## Abstract

Animals are strongly connected to the environments they live in and may become adapted to local environments. Examining genetic–environment associations of key indicator species, like seabirds, provides greater insights into the forces that drive evolution in marine systems. Here we examined a RADseq dataset of 19,213 SNPs for 99 rhinoceros auklets (Cerorhinca monocerata) from five western Pacific and 10 eastern Pacific breeding colonies. We used partial redundancy analyses to identify candidate adaptive loci and to quantify the effects of environmental variation on population genetic structure. We identified 262 candidate adaptive loci, which accounted for 3.0% of the observed genetic variation among western Pacific and eastern Pacific breeding colonies. Genetic variation was more strongly associated with pH and maximum current velocity, than maximum sea surface temperature. Genetic–environment associations explain genetic differences between western and eastern Pacific populations; however, genetic variation within the western and eastern Pacific Ocean populations appears to follow a pattern of isolation‐by‐distance. This study represents a first to quantify the relationship between environmental and genetic variation for this widely distributed marine species and provides greater insights into the evolutionary forces that act on marine species.

Examining adaptive genetic variation of key indicator species, like seabirds, provides greater insights into the forces that drive evolution in marine systems. Here we examined a ddRAD dataset of 19,213 SNPs for 99 rhinoceros auklets (Cerorhinca monocerata) from five west Pacific and 10 east Pacific breeding colonies. Our analyses provide evidence for local adaption between western and eastern Pacific populations; however, we did not find evidence for local adaptation within populations from either the west Pacific or the east Pacific.