Candidate gene–environment interactions and their relationships with timing of breeding in a wild bird population

Abstract

Monitoring and predicting evolutionary changes underlying current environmental modifications are complex challenges. Recent approaches to achieve these objectives include assessing the genetic variation and effects of candidate genes on traits indicating adaptive potential. In birds, for example, short tandem repeat polymorphism at four candidate genes (CLOCK, NPAS2, ADCYAP1, and CREB1) has been linked to variation in phenological traits such as laying date and timing of migration. However, our understanding of their importance as evolutionary predictors is still limited, mainly because the extent of genotype–environment interactions (GxE) related to these genes has yet to be assessed. Here, we studied a population of Tree swallow (Tachycineta bicolor) over 4 years in southern Québec (Canada) to assess the relationships between those four candidate genes and two phenological traits related to reproduction (laying date and incubation duration) and also determine the importance of GxE in this system. Our results showed that NPAS2 female genotypes were nonrandomly distributed across the study system and formed a longitudinal cline with longer genotypes located to the east. We observed relationships between length polymorphism at all candidate genes and laying date and/or incubation duration, and most of these relationships were affected by environmental variables (breeding density, latitude, or temperature). In particular, the positive relationships detected between laying date and both CLOCK and NPAS2 female genotypes were variable depending on breeding density. Our results suggest that all four candidate genes potentially affect timing of breeding in birds and that GxE are more prevalent and important than previously reported in this context.

Clockgene polymorphism, migratory behaviour and geographic distribution: a comparative study of trans‐Saharan migratory birds

“…, ; Bazzi et al . , ; Bourret & Garant ). Such an among‐species variability in candidate gene diversity could be associated with migratory behaviour and/or geographic distribution.…”

“…, ; Bazzi et al . ; Bourret & Garant ). Moreover, we tested the hypothesis that species breeding at more northern latitudes have longer Clock alleles.…”

Circadian genes polymorphism and breeding phenology in a resident bird, the yellow‐legged gull

“…Moreover, Adcyap1 polymorphism has been mainly linked to dispersal (Chakarov et al ., ) or migratory behaviour, and in some species it predicts migration distance or breeding latitude among populations (Mueller et al ., ; Peterson et al ., ; Mettler et al ., ; Bazzi et al ., ). To date, only one study (Bourret & Garant, ) disclosed a complex genotype by environment interaction on breeding date: in female tree swallows ( Tachycineta bicolor ), Adcyap1 length polymorphism did not predict laying dates per se (see also Chakarov et al ., ), but depending on the breeding latitude (Bourret & Garant, ). We note that a lack of the association between length polymorphism in the Adcyap1 gene and breeding phenology can be explained by the observed genetic variability of this gene, which is markedly lower than that disclosed in other species (Chakarov et al ., ; Bourret & Garant, ; Bazzi et al ., , b).…”

“…A flourishing body of studies has recently identified some of these phenological genes, conserved among phylogenetically distant taxa, whose polymorphism has been invoked to explain differences in the photoperiodic responses among individuals and populations (Johnsen et al ., ; O'Malley & Banks, ; O'Malley, Ford & Hard, ; Bourret & Garant, ; Saino et al ., ). Although polymorphism can be found in several gene regions, most of such studies focused on the presence of tandem repeats which are involved in their regulatory functions, and suggested that their length polymorphism is, at least partly, controlling inter‐individual variability in phenological traits (Kashi, King & Soller, ; Li et al ., ; Fondon et al ., ).…”

“…Length variation in this Adcyap1 region has been linked to migratory behaviour (Mueller, Pulido & Kempenaers, ; Peterson et al ., ; Mettler, Segelbacher & Schaefer, ; Bazzi et al ., ), and dispersal propensity (Chakarov et al ., ) in some populations, with longer alleles being associated with longer migration distances or earlier natal dispersion. In addition, Adcyap1 polymorphism predicted within population breeding date depending on breeding latitude (Bourret & Garant, ). However, in other populations and species, no significant association between Adcyap1 genotype and phenological traits has been detected (Peterson et al ., ; Saino et al ., ).…”