2.6.3 Population genetic analyses
Allelic richness (Ar ), observed (Ho ) and
expected heterozygosity (He ), and inbreeding
coefficient (Fis ) were calculated with the R package ‘diveRsity’
v.9.90
(Keenan,
Mcginnity, Cross, Crozier, & Prodöhl, 2013) from microsatellite data
of 613 individuals from 22 populations (see section 2.3). Each locus
and population was tested for Hardy-Weinberg equilibrium using the R
package ‘genepop’
v.1.1.7
(Rousset, 2008). To assess if Fis is positively correlated with
homostyle frequency we used a standard linear model with homostyle
frequency as independent variable. Given that population size can
influence Fis, we included census size as covariable with no
interaction among independent variables.
Population specific and pairwise genetic differentiation measured asFst(Weir
& Cockerham, 1984) and its normalized counterpart G’st(Meirmans
& Hedrick, 2011) were estimated with the R package ‘diveRsity’ v.9.90
(Keenan et al., 2013). To discover whether increasing homostyle
frequencies correspond to increased genetic differentiation, we tested
whether pairwise differences in homostyle frequencies between
populations are positively correlated with pairwise G’st values.
To test the significance of association between these two matrices, we
used a Mantel test as implemented in the R package
‘adegenet’ v2.1.3
(Jombart,
2008).