Abstract Detail

Systematics Section/ASPT

Mastin, Jared [1], Bruederle, Leo [1], Yakish, Eileen [1].

Evidence for Genetic Allopolyploidy in Eutrema edwardsii R. Br. (Brassicaceae).

Eutrema edwardsii R. Br. (Brassicaceae) is an arctic-alpine mustard with a near circumpolar distribution. Its closest relative, E. penlandii Rollins, is a federally listed, threatened species that is endemic to the Mosquito Range in the Southern Rocky Mountains. As part of a larger project addressing the systematics of the genus in North America, we used allozyme analysis to characterize genetic diversity and structure within and among populations of the two species. This was coupled with chromosome counts that were used to determine ploidy in E. penlandii, specifically, which has not been previously documented. Our results reveal that E. penlandii is diploid, in contrast to previously published chromosome counts of E. edwardsii, which exists as a tetraploid, hexaploid, and octaploid for which we assumed an autopolyploid origin. However, allozyme analysis revealed an allopolyploid origin for E. edwardsii as evidenced from fixed heterozygosity involving two and three genomes for tetraploids and hexaploids, respectively. Allopolyploidy is the result of hybridization of two divergent species and chromosome doubling which leads to disomic inheritance of homologous chromosomes resulting in fixed heterozygosity, which is diagnostic with allopolyploidy. Our data further suggest that E. penlandii is one of the progenitors to E. edwardsii, although the identity of the other progenitors cannot be elucidated from these data. Some controversy exists over the classification of the two Eutrema species, which has implications for conservation. These data support the recognition of E. penlandii as distinct. Phylogenetic data currently being collected should provide further insight into the evolutionary history of genus Eutrema.

Broader Impacts:

1 - University of Colorado Denver, Integrative Biology, Campus Box 171, Denver, CO, 80217-3364, USA

Keywords:
Eutrema
Brassicaceae
allopolyploidy
threatened species.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSY037
Abstract ID:524
Candidate for Awards:None