Systematics Research Lab

Plant Systematics Research

Gardens are an invaluable resource for botanical research, providing specimens and material of species from around the world. In The Huntington’s molecular systematics lab, the botanical staff investigates fundamental processes of plant evolution using cutting-edge methods combined with traditional fieldwork. Systematics research is the understanding and documentation of biological diversity and the processes that produce it. The lab’s current focus is on speciation, phylogeography, phylogenetics, and biogeography in the cycad genus Dioon.

Dioon is one of 10 living genera of cycads, with 17 species mostly endemic to Mexico and one in Honduras. While they may look a bit like palm trees, they are actually gymnosperms—they make seeds but not flowers—and are relatives of gingkoes and pines. Cycads in general are mostly found in tropical and subtropical habitats. The species of Dioon can be found across all of the major mountain systems of Mexico, with the center of diversity for this genus in southern Mexico, south of the Trans-Mexican Volcanic Belt. Populations range from several hundred to only a few dozen individuals and most species are considered vulnerable or endangered, which is why they are protected. Species are distinguished by relatively subtle characteristics, many quite similar to each other. This suggests some interesting possibilities for their evolutionary history—including recent divergence from a common ancestor and/or hybridization between species.

Reconstructing Dioon Evolutionary History

The purpose and goal of the research is to reconstruct the evolutionary history and genetic diversity of these species to better understand the processes that have led to their diversity and distribution, and to inform conservation efforts both in Mexico and at institutions such as The Huntington. Questions we hope the research will answer include:

• What are the evolutionary relationships among species?
• What has driven speciation in this group?
• What are the true species boundaries in Dioon?
• What is the genetic diversity of populations and how isolated are they from each other?
• What is the timing of divergence and any hybridization events among species?

Conservation Genetics in Cycads

The goal of conservation genetics is to document and explain patterns of genetic diversity within species in order to inform conservation efforts and planning. As 65% of all cycad species are threatened with extinction, there is an urgent need for this work. Projects in and are underway at The Huntington in collaboration with partners in the Global Conservation Consortium for Cycads. We use samples from botanical gardens, including The Huntington, and from native populations in the wild, to estimate patterns of gene flow, genetic variation, and historical demography within threatened species.