Phenotypic trait variation in the North American Tragopogon allopolyploid complex.

Premise: Recently formed allopolyploids Tragopogon mirus and T. miscellus and their diploid parental species, T. dubius, T.

Polyploidy and mutation in Arabidopsis.

The effects of genetic mutations are influenced by genome structure. Polyploids have more gene or allele copies than diploids, which results in higher tolerance of recessive deleterious mutations. However, this benefit may differ between autopolyploids and allopolyploids and between neopolyploids and older polyploid lineages due to the effects of hybridization and diploidization, respectively.

Habitat Shape Affects Polyploid Establishment in a Spatial, Stochastic Model.

Polyploidy contributes massively to the taxonomic and genomic diversity of angiosperms, but certain aspects of polyploid evolution are still enigmatic. The establishment of a new polyploid lineage following whole-genome duplication (WGD) is a critical step for all polyploid species, but this process is difficult to identify and observe in nature. Mathematical models offer an opportunity to study this process by varying parameters related to the populations, habitats, and organisms involved in the polyploid establishment process.

Karyotypic variation and pollen stainability in resynthesized allopolyploids Tragopogon miscellus and T. mirus.

Premise Of The Study: Polyploidy has extensively shaped the evolution of plants, but the early stages of polyploidy are still poorly understood. The neoallopolyploid species Tragopogon mirus and T. miscellus are both characterized by widespread karyotypic variation, including frequent aneuploidy and intergenomic translocations.

Increased heterosis in selfing populations of a perennial forb.

Quantifying the importance of random genetic drift in natural populations is central to understanding the potential limits to natural selection. One approach is to estimate the magnitude of heterosis, the increased fitness of progeny derived from crosses between populations relative to crosses within populations caused by the heterozygous masking of deleterious recessive or nearly recessive alleles that have been fixed by drift within populations. Self-fertilization is expected to reduce the effective population size by half relative to outcrossing, and population bottlenecks may be common during the transition to selfing.