Long-insert sequence capture detects high copy numbers in a defence-related beta-glucosidase gene βglu-1 with large variations in white spruce but not Norway spruce by Hung, TIN, Wu, ETY, Zeltiņš, P, Jansons, Ā, Ullah, A, Erbilgin, N, Bohlmann, J, Bousquet, J, Birol, I, Clegg, S, Mackay, J