Fig. 4

Mean heterozygosity in different SNP classes. The gray dotted lines represent the overall mean observed heterozygosity based on all genotyped SNPs. Non-syn stands for Non-synonymous. The mean heterozygosities of the SNP classes differed significantly from the overall mean (Welch two sample t-test p < 0.05), except for the 3′UTR and 5′UTR classes. Standard errors (SE) of the means were lower than 0.004 for the overall SNPs and for all different SNP classes, except for the 5′UTR class, which had SE = 0.009. Bars with different letters represent a significant difference in the mean heterozygosity within the same level, e.g. difference between ‘Non-genic’ and ‘Genic’ classes on the first level or difference between ‘Non-synonymous’ and ‘Synonymous’ classes on the third level