From Gels to Genomics: The Evolving Landscape of Pteridology. A Celebration of Gerald Gastony's Contributions to Fern Evolutionary Biology
Nakazato, Takuya .
The Ceratopteris richardii Linkage Map: Fern genome organization, evolution, and the evolution of reproductive isolation.
Homosporous ferns have extremely high chromosome numbers, and yet the species with the lowest chromosome numbers show diploid gene expression patterns, suggesting that they may be diploidized ancient polyploids. A high-resolution linkage map of Ceratopteris richardii suggested that although past polyploidization is a potential mechanism for the observed abundance of gene duplicates, small-scale duplications may be the primary mode of gene duplication in C. richardii. Alternatively, evidence of past polyploidization may be masked by extensive chromosomal rearrangements following polyploidization(s). Examination of marker transmission ratio distortion (TRD) and spore germination rates revealed substantial reproductive barriers between the parental races, predominantly in the form of spore inviability. Intrinsic genetic factors such as Bateson–Dobzhansky–Muller (BDM) incompatibilities involving both nuclear–nuclear and nuclear–cytoplasmic factors and chromosomal rearrangements appear to contribute to intrinsic postzygotic isolation. The genomewide distribution patterns of TRD loci support the hypothesis that reproductive barriers are a byproduct of divergence in allopatry.
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1 - Indiana University, Department of Biology, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Room 5/Woodward
Date: Tuesday, July 29th, 2008
Time: 10:30 AM