Postdoctoral Fellow HudsonAlpha Institute for Biotechnology Huntsville, Alabama
Body of Abstract: The Cannabaceae family has a deep history regarding their dioecious flowers and sex chromosomes. One century ago, the XY pair that controls the development of the sexes was identified in the beer hop Humulus lupulus var. lupulus, owing to the cytologically smaller Y chromosome relative to the X. Curiously, examinations across other species in Humulus and in the sister genera Cannabis uncovered varying cytological differences. Some of the Ys were bigger than the X and some evolved multiple pairs of XYs. Despite these early discoveries, we know little about the Cannabaceae sex chromosomes at the molecular level. This is largely due to the complexities of assembling XY pairs in genome references. Here we use a combination of Illumina, PacBio HiFi, and Dovetail Omni-C data to assemble fully-phased genomes for XY males of three varieties of Humulus, two cultivars of Cannabis, and one Morus as a comparative out group. We show that our assemblies match the known cytological differences in these XY pairs. We next use these six assemblies to explore the timing of evolution, structural complexity, and evolutionary diversity of these XY chromosomes and begin to uncover genes that control the development of the economically valuable female flowers in hemp and hop.