R&D CENTER

Genome-Wide Approach Based on Target-Enrichment NGS Sequencing Suggested Ancient Hybridizations in Magnoliaceae: Preliminary Results

Sangtae Kim, Suhyeon Park, Jongsun Park
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Reconstruction of the phylogeny of Magnoliaceae, a member of early-diverging angiosperms, plays a key role in understanding the diversification of angiosperms. With the development of new molecular techniques, various phylogenetic studies on Magnoliaceae have been conducted such as studies based on chloroplast RFLP, and sequencing of single gene, multiple genes, and chloroplast whole genome. However, the evolution of Magnoliaceae remains unclear in many parts, especially the relationships among major sublineages in the family because overall base substitution rate in Magnoliaceae is very low, as compared to other angiosperm groups. In this study, we used a genome-wide approach on the phylogeny of Magnoliaceae with high throughput target-enrichment NGS sequencing. We identified 504 putative single/low copy gene regions (443 kbp) as targets for captured NGS sequencing. These regions are 1) expressed single-copy genes extracted from a preliminary genome assembly of Magnolia kobus (ver. 0.4; see talk 1401) using gene clustering (Tribe-Mcl) with its transcriptomes and 2) shared single/low copy genes among Arabidopsis, Polulus, Oryza, Vitis, and M. kobus. As a preliminary result, we determined chloroplast genomes (ca. 136 kbp excluding one IR) and 20 nuclear DNA regions (ca. 24 kbp) for 130 taxa representing all previously reported sublineages of Magnoliaceae. Chloroplast regions and nuclear regions produced robust phylogenetic trees. However, some conflict relationships were recognized between these trees. This suggests possible ancient hybridizations, especially between subgroups of MICHELIA and YULANIA clades. The results will provide a basis for the evolutionary diversification in the family as well as new classification system of Magnoliaceae.