Phased chromosome‐level genomes reveal young evolutionary origin of sex determination in Magnolia kwangsiensis

While sex determination has been extensively studied in animals, the origin and early evolution of sex chromosomes in plants remain poorly understood. Magnolia kwangsiensis, an early-diverging dioecious flowering plant, provides a unique opportunity to investigate sex chromosome evolution at early stages. Here we generated phased chromosome-level genome assemblies for male and female M. kwangsiensis individuals (~2.4-2.5 Gb of 19 chromosomes) and uncovered a nascent XY sex chromosome system. The