Genome scanning for detecting adaptive genes along environmental gradients in the Japanese conifer,Cryptomeria japonica

Local adaptation is important in evolutionary processes and speciation. We used multipletests to identify several candidate genes that may be involved in local adaptation from1026 loci in 14 natural populations of Cryptomeria japonica, the mosteconomically important forestry tree in Japan. We also studied the relationships betweengenotypes and environmental variables to obtain information on the selective pressuresacting on individual populations. Outlier loci were mapped onto a linkage map, and thepositions of loci associated with specific environmental variables are considered. Theoutlier loci were not randomly distributed on the linkage map; linkage group 11 wasidentified as a genomic island of divergence. Three loci in this region were alsoassociated with environmental variables such as mean annual temperature, daily maximumtemperature, maximum snow depth, and so on. Outlier loci identified with high significancelevels will be essential for conservation purposes and for future work on molecularbreeding.