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Convergence, Constraint And The Role Of Gene Expression During Adaptive Radiation: Floral Anthocyanins In Aquilegia, Justen B. Whittall, Claudia Voelckel, Daniel J. Kliebenstein, Scott A. Hodges
Convergence, Constraint And The Role Of Gene Expression During Adaptive Radiation: Floral Anthocyanins In Aquilegia, Justen B. Whittall, Claudia Voelckel, Daniel J. Kliebenstein, Scott A. Hodges
Biology
Convergent phenotypes are testament to the role of natural selection in evolution. However, little is known about whether convergence in phenotype extends to convergence at the molecular level. We use the independent losses of floral anthocyanins in columbines (Aquilegia) to determine the degree of molecular convergence in gene expression across the anthocyanin biosynthetic pathway (ABP). Using a phylogeny of the North American Aquilegia clade, we inferred six independent losses of floral anthocyanins. Via semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we monitored developmental and tissue-specific variation in expression of the six major structural ABP loci in three Aquilegia species, two that …
The Evolution Of Organismal Complexity In Angiosperms As Measured By The Information Content Of Taxonomic Descriptions, J. Gordon Burleigh, Justen B. Whittall, Michael J. Sanderson
The Evolution Of Organismal Complexity In Angiosperms As Measured By The Information Content Of Taxonomic Descriptions, J. Gordon Burleigh, Justen B. Whittall, Michael J. Sanderson
Biology
We describe an information theoretic method for measuring relative organismal complexity. The complexity measure is based on the amount of information contained in formal taxonomic descriptions of organisms. We examine the utility of this measure for quantifying the complexity of plant families. The descriptions are subjective by nature, but we find a significant correlation in the complexity values of plant families from two independently authored sets of formal taxonomic descriptions. An analysis of the evolution of complexity across angiosperms found evidence of a pattern of increasing complexity. Our measure of complexity provides an operational definition of complexity that may be …
A Survey Of Nuclear Ribosomal Internal Transcribed Spacer Substitution Rates Across Angiosperms: An Approximate Molecular Clock With Life History Effects, Kathleen M. Kay, Justen B. Whittall, Scott A. Hodges
A Survey Of Nuclear Ribosomal Internal Transcribed Spacer Substitution Rates Across Angiosperms: An Approximate Molecular Clock With Life History Effects, Kathleen M. Kay, Justen B. Whittall, Scott A. Hodges
Biology
Background: A full understanding of the patterns and processes of biological diversification requires the dating of evolutionary events, yet the fossil record is inadequate for most lineages under study. Alternatively, a molecular clock approach, in which DNA or amino acid substitution rates are calibrated with fossils or geological/climatic events, can provide indirect estimates of clade ages and diversification rates. The utility of this approach depends on the rate constancy of molecular evolution at a genetic locus across time and across lineages. Although the nuclear ribosomal internal transcribed spacer region ( nrITS) is increasingly being used to infer clade ages in …