Systematics and Phylogenetics

Systematics and Phylogenetics

Research in my lab has extensively studied systematics and phylogenetics of lineages within Malvaceae. Some particular focal groups have been:

The genus Adansonia

David’s did his dissertation on the pollination biology and systematics of baobabs research and started using molecular systematic approaches as a post-doc. While this work was on the back-burners for many years, we have returned to this group recently, thanks to recent funding from the NSF and a constructive collaboration with the Wendel/Grover lab at Iowa State University and with UW colleague, Cécile Ané. Under the local leadership of Nisa Karimi, we are studying several questions:

  1. Is the putative, diploid African baobab species, A. kilima, distinct from the familiar, tetraploid, A. digitata, and is A. kilima actually diploid?
  2. What is the pattern of genetic relatedness across continental Africa? Does it reveal historical patterns of migration?
  3. What are the relationships among the six recognized Malagasy species? Do the four, long-flowered, hawkmoth pollinated species, all of which have yellow/red floral organs, form a clade? Has there been any introgression/hybrid speciation?
  4. What are the relationships among three closely related Malagasy species: A. za, A. madagascariensis and A. perrieri? Are they distinct taxa or a single species complex with clinal variation and/or introgression?
  5. What causes the great variation among individuals African baobab trees in there fruit set? What role does pollinator movement and late-acting self-incompatibility play in explaining this variation.

We are addressing these questions using a diversity of techniques including multilocus phylogenetics using targeted sequence capture and next-gen sequencing, flower cytometry, chromosome counting, pollination observations, and field reproductive biology experiments.

 

Other groups of Malvaceae we have studied or are studying:

Bombacoideae: Over the years we have published a number of papers on the broad scale phylogeny of Malvaceae, with a special focus on the bombacoid clade. Historically this work was lead by a former post-doc and collaborator, Bil Alverson. Another former post-doc Maria von Balthazar studied floral development in the group. Ongoing research in bombacoid phylogeny involves an international team, built by Brazilian collaborator Jefferson Sobrinho.

Malvoideae: In the past graduate student Maggie Koopman (now Hanes) studied the phylogeny of Malagasy Malvoideae, with a focus on Hibiscus s.lat. Maggie continues this work in her own lab at Eastern Michigan University. Current graduate student Melody Sain, is focusing on North American Malveae, especially the genera Callirhoe and Napaea.

Byttnerioideae: Former graduate student Barbara Whitlock, now with her own lab at Miami University, studies the phylogeny of the Byttnerioideae clade, which includes the source of chocolate (Theobroma).

Durioneae: Former post-doc Reto Nyffeler, now a curator at the Institut für Systematische und Evolutionäre Botanik in Zurich, studied the phylogeny and evolution of the clade that includes the famous (and famously stink) durian fruit.

Some other systematic/phylogenetic projects

Iochroma (Solanaceae). Studied by former graduate student Stacey Smith, who continues to study this group in her own laboratory at the University of Colorado, Boulder.

Scaevola (Goodeniaceae). Studied by former graduate student, Dianella Howarth, who continues to work on Goodeniaceae and related families as a professor at St. John’s University.

Euphorbia (Euphorbiaceae). Studied by former graduate student Ivalú Cacho, now a professor at the Universidad Nacional Autónoma de México (UNAM).