Next SOL Seminar Online will be presented by Steven Dodsworth on The recent radiation of Nicotiana section Suaveolentes in Australia: cytogenetic, ecological, and phylogenomic insights
Abstract. Nicotiana section Suaveolentes represents over half of the genus, an enigmatic group of plants with an allotetraploid origin. Species are mostly distributed across Australia, with a few taxa in the South Pacific (New Caledonia, Tonga, Marquesas Islands), and one endemic to Namibia. Their evolution has been previously intractable, with low or no resolution in standard phylogenetic markers, and limited verified wild material available. Collections amassed over the past decade have been the foundation of a revised phylogenomic framework for section Suaveolentes, using Hyb-Seq and RADseq approaches, and in the face of incomplete lineage sorting. Chromosome number appears to have dropped independently a number of times and is uncorrelated with genome size, which has generally reduced as part of the diploidisation process. From a polyploid origin (n = 24) species represent a dysploid series with reducing chromosome numbers (n = 24 – 15) almost down to the diploid number for the genus. Intriguingly, the highest concentration of species is found in the arid centre of Australia, and species show different strategies for coping with drought conditions. Using ecological niche modelling we show that pairwise niche overlap correlates with phylogenetic distance, but that low levels of overlap are found overall, suggesting a mixed picture of niche conservatism and a possible role for niche divergence in speciation. Overall these results paint N. section Suaveolentes as a group undergoing recent radiation, with concomitant changes in genome size, chromosome number and ecology underpinning their diversification.
When? Friday 29th January 3 pm (GMT+1)
The zoom link to join the meeting is https://cuboulder.zoom.us/j/94333146166 Meeting ID: 943 3314 6166, password: Solanaceae
Watch this talk here: https://youtu.be/ILbFFSGuQPg