Abstract Detail

Bryological and Lichenological Section/ABLS

Wickett, Norman [1], Liu, Yang [2], Shaw, Jonathan [3], Goffinet, Bernard [2].

Reconstructing the rapid radiation of pleurocarpous mosses using genomic approaches.

The Bryophyta (mosses) compose one of the oldest lineages of extant land plants; their unique tree of life deeply rooted in the early Devonian. Despite their haploid vegetative body and their inability to develop branched sporophytes with multiple sporangia, mosses have avoided extinction. In fact, mosses have not simply survived in an ecological refugium sheltered from strong selection forces, some lineages have dramatically diversified, as recently as in the Miocene. Today, bryophytes comprise ± 12,000 species distributed throughout the world. Their vegetative body is fundamentally simple: an axis with spirally inserted leaves. However, each leaf bears in its axil a primordium, providing an opportunity for branching. The moss body is fundamentally modular, composed of a single or numerous modules distributed among four hierarchical ranks. This modularity allows for the functional specialization of branches. Such opportunities may have been best exploited in the ancestor to the Hypnanae, the crown group of mosses, a lineage composed of ± 5200 species (i.e., 45% of moss diversity). This group has traditionally been defined by short reproductive branches and hence the lateral (“pleuro”) distribution of their sex organs (“carps”). The main module is thereby freed of a reproductive function and maintains perennial vegetative growth. Today, pleurocarpous mosses dominate the ground vegetation in the boreal forests and the epiphytic communities in temperate and tropical rainforests. In these ecosystems they play critical roles in regulating nutrient fluxes and water movement, hence indirectly affecting productivity of the forests. Around 5,200 species distributed among slightly over 500 genera compose the Hypnanae. This lineage underwent an explosive radiation during the Jurassic as angiosperms began their rise to prominence. Transitions between a terricolous, epiphytic and even aquatic habitats occurred repeatedly and in all directions, often erasing the morphological signatures of the species’ past evolutionary history. Consequently, the circumscription of and the relationships among genera as proposed based on morphological traits are widely contradicted by phylogenetic inferences from DNA data. However, genetic divergence at discrete loci is weak, and alternative systematic hypotheses remain tentative. Here we describe a collaborative effort using the latest developments in gene enrichment and genome sequencing to 1) infer robust phylogenetic hypotheses for the macroevolutionary tree of mosses with a emphasis on the diversification of the crown group mosses, the Hypnanae, which hold over 40% of taxic diversity.

Broader Impacts:

1 - Chicago Botanic Garden, 1000 Lake Cook Rd., Apt 2, Glenco, IL, 60022, USA
2 - University of Connecticut, Department of Ecology & Evolutionary Biology, 75 N. Eagleville Road, U-3043, STORRS, CT, 06269-3043, USA
3 - Duke University, Biology, NC, 27708

Keywords:
Bryophytes
Genomics
Phylogenetics
rapid radiation
transcriptomes.

Presentation Type: Oral Paper:Papers for Sections
Session: 29
Location: Ascot/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 3:00 PM
Number: 29008
Abstract ID:849
Candidate for Awards:None