Molecular Analysis of Evolution and Origins of Cultivated Hawthorn ( Crataegus spp.) and Related Species in China

Hawthorn is of high economic value owing to its medicinal properties and health benefits. is a member of the Rosaceae family; the genus has a complicated taxonomic history, and several theories on its origin have been proposed. In this study, 53 accessions from seven taxa native to China and accessions of exotic species (two from Europe and one from North America) were analyzed by specific locus amplified fragment sequencing (SLAF-seq). In total, 933,450 single-nucleotide polymorphisms were identified after filtering and used to investigate the species' genomic evolution. Phylogenetic trees derived from nuclear simple sequence repeats (SSRs) and SLAF-seq data showed the same topology, in which and formed a closely related cluster that was clearly separated from the cluster composed of , , var. , and . Phylogenetic and structure analysis indicated that the seven Chinese taxa had two separate speciation events. Plants that evolved the southwestern route shared the genepool with the European species, whereas plants along the northeastern route shared the genepool with the North American species. TreeMix genetic analysis revealed that may have a hybrid origin. This study provides valuable information on the origins of Chinese and suggests an evolutionary model for the main species that native to China.