Collaborative Research: Species definitions and phylogenetic relationships within Isoetes (Isoetaceae) Using Multiple Data Sets

Milwaukee Public Museum, Milwaukee WI

Investigators

Abstract

9981501 Taylor Species Delimitation and Phylogenetic Relationships within Isoetes Using Multiple Data Sets Isoetes are a genus of nonflowering plants which were widespread during ancient times (Paleozoic). They have a worldwide distribution and diverse ecological adaptations. Isoetes plants may be found in streams , lakes, and ephemeral pools. The form of the plant is very simple, consisting of narrow, elongated leaves which produce spores at their base and a swollen root stock. This simple form (morphology) provides few characters, making the identification of species and determination of species relationships difficult. In addition, Isoetes species readily hybridize with each other, further confusing our understanding of species limits and relationships. This project has three main objectives: 1) to provide an evolutionary tree (phylogeny) for the genus throughout the world, 2) to identify and delimit species within Isoetes, and 3) to identify the original parents involved in the formation of hybrid species. Since morphology provides few characters for this group, additional molecular data in the form of DNA sequences will be collected. In the past ten years, DNA sequence data have been an invaluable tool, helping scientists understand evolutionary relationships in a wide variety of organisms. To better understand relationships of Isoetes species worldwide, we will use two DNA regions, one located in the chloroplast genome (atpB/rbcL intergenic spacer region) and one in the nucleus (internal transcribed spacer regions - ITS). To define species and determine the origin of hybrid species, we will use a highly variable region within a gene involved in plant reproduction (LEAFY second intron). This work is a collaborative effort between Drs. Sara B. Hoot (University of Wisconsin-Milwaukee) and W. Carl Taylor (Milwaukee Public Museum). S. Hoot will be largely responsible for the molecular work, C. Taylor will be involved in plant collection (taking him to distant sites in South America, Africa and other continents) and morphological studies of Isoetes.