A brief summary of the evolutionary history of the baobab trees
My research is focuses on the baobab trees, eight species that collectively comprise the genus Adansonia (Malvaceae). The genus has an interesting biogeographical pattern with one species found widespread across continental Africa, six endemic to Madagascar, and one species endemic to Northwestern Australia.
Baobabs have an incredible floral diversity with two pollination guilds, mammal- and hawkmoth-pollinated. The African baobab's floral morphology fit the classic bat-pollination syndrome with evidence for such in East and West Africa. However, no bats have been seen pollinating trees in South Africa. After performing a series of pollination treatments and investigating nectar & floral scent phenotypes, we found evidence for geographic variation in these floral traits which appear to correlate with shifts in pollination system (hawkmoths). The six species of baobab endemic to Madagascar often occur in sympatry and molecular data (Baum et al., 1998) has suggested possibly gene flow and introgression between some species pairs. More recent genetic work further corroborates the possibility of hybridization (Leong Pock Tsy et al., 2013) and a recent expedition to Madagascar resulted in identifying morphological intermediates. Using genetic data and sampling across each species geographical ranges, we find evidence for deep reticulation which help explain apparent floral homoplasy and pollination shifts in this group. |
Phylogeography of the African baobab, Adansonia digitata
The African baobab is an important ethnobotanical species across its range as well as in places of introduction. I'm investigating the species geographic origins and historical patterns of migration across Africa, associating genetic structuring and morphological traits. I am also testing the hypotheses that seeds naturally disperse via water with evidence of geographic structuring based on watersheds, though this may be confounded by seemingly extensive human-assisted dispersal.
The African baobab is an important ethnobotanical species across its range as well as in places of introduction. I'm investigating the species geographic origins and historical patterns of migration across Africa, associating genetic structuring and morphological traits. I am also testing the hypotheses that seeds naturally disperse via water with evidence of geographic structuring based on watersheds, though this may be confounded by seemingly extensive human-assisted dispersal.
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