Abstract Detail


Rees, Riley J. [1], Schenk, John [2].

Evolutionary History of Caryophyllaceae Using DNA sequences.

Petals are the attractive structures of flowers that entice pollinators and drive species diversification, however, mounting evidence suggests that petals have evolved numerous times throughout the angiosperms. Petals of many of the early lineages of angiosperms, such as the water lilies, evolved from sepals, while the clade that includes the monocots and eudicots have evolved petals from stamen structures. Even when examining more recently evolved lineages in the eudicots, we find the evolution of petals to be quite dynamic. Caryophyllaceae (the carnation family), for example, is believed to ancestrally lack petals, and instead re-evolved them later in the lineage. But how did petals evolve in the family? We observe sterile stamen structures resembling petals called staminodes early in the Caryophyllaceae phylogeny, but it remains unclear if the petal structures evolved from, or independently of, those staminodes. Studying the evolutionary transitions from apetalous flowers to those with staminodes on to those with petal-like structures can provide insight into the early evolution of petals in the angiosperms. Before we are to understand the transitions that have led to the re-evolution of petals, we must first understand the evolutionary relationships among species in the family. Our project uses genetic information contained within DNA to identify the evolutionary relationships of genera within Caryophyllaceae. To reconstruct the Caryophyllaceae phylogeny, we selected three genes from the chloroplast genome and one nuclear gene and conducted model-based analyses to infer relationships and support values. These genes are maturase-K (matK), the intergenic spacer regions 1 and 2 (ITS-1 and ITS-2), and the TrnL–TrnF intergenic region. They were chosen because they have been sampled widely across the family and provide adequate molecular variation for phylogeny reconstruction as intergenic regions have little to no selective pressure altering mutation rates. Some sequences were sampled from GenBank, and additional sequences have been found using PCR and Sanger sequencing. Relationships based on phylogenetic reconstructions and their importance to our understanding of floral evolution will be discussed.

1 - 48 East Green Dr., Room 317, Athens, OH, 45701, United States
2 - Ohio University, Department Of Environmental And Plant Biology, 22 Richland Ave., 401 Porter Hall, Athens, OH, 45701, United States

targeted sequencing
Floral Development.

Presentation Type: Poster
Number: PPL005
Abstract ID:388
Candidate for Awards:None

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