Speaker: Toby Kellogg, Danforth Plant Science Center principal investigator

Title: Diversification in the grass tribe Andropogoneae 

Abstract: Nearly one fifth of the world’s land area is inhabited by wild grasses of a single clade, the tribe Andropogoneae, which originated about 20 million years ago in the early Miocene.  A cultivated member of this same tribe, maize, now replaces wild grasses in many areas, dominating the landscape and the world’s economy.  The tribe is characterized by spikelets borne in pairs, with the spikelet pair forming an integrated developmental unit that has been extensively modified among more than 1000 species. The spikelet pair is also the dispersal unit, with aerodynamic properties consistent with wind dispersal for most species. The tribe spread throughout the Old World, arriving later to the Americas as the result of several independent dispersal events. Newly generated genome sequences for members of the tribe indicate collinearity of genomes, with the ancestral haploid number and architecture of 10 chromosomes being preserved even through polyploidization events. A large nuclear phylogeny points to the source of one of the maize subgenomes and permits hypotheses about the selective forces driving diversification of Zea and its sister genus Tripsacum. 

Host: Josh Strable, GDCB assistant professor