Ancient structural variants control balanced mating morphs is walnuts and pecans

The maintenance of stable mating type polymorphisms is a classic example of balancing selection. One lesser known but intriguing example of a balanced mating polymorphism in angiosperms is heterodichogamy - polymorphism for opposing directions of male and female flowering times in hermaphrodites. This mating system is common throughout Juglandaceae, the family that includes walnuts (Juglans), as well as pecan and other hickories (Carya). I’ll discuss our resulting mapping the locus in each genus, where we find two ancient (>50 Mya) structural variants involving different genes that both segregate as genus-wide trans-species polymorphisms.

Speaker: Graham Coop, UC Davis