A molecular investigation into the origin and relationships of karaka/kōpi (Corynocarpus laevigatus) in New Zealand

Corynocarpus is a small, morphologically and phylogenetically isolated genus of trees from the southwest Pacific. We examined the phylogeny of Corynocarpus using the nuclear WAXY and ITS loci. Our molecular dating, when examined in combination with other published molecular dating studies, indicates that the origin of the genus and the arrival of Corynocarpus in New Zealand are likely to be much more recent than previously suggested. A second focus of our study was to investigate patterns of pre-European putative translocation of C. laevigatus (karaka, kōpi) by Māori throughout New Zealand using diversity at these two loci. Our New Zealand-wide sampling revealed the distinctiveness of specimens from the Three Kings Islands at both loci, precluding the Three Kings Islands as the source population for translocated C. laevigatus. However, the low level of sequence variation at these loci prevented further insight into the human-mediated dispersal of this species.