Abstract Detail

Recent Topics Posters

Hosseinalizadehnobarinezhad, Mahboubeh [1], Wallace, Lisa [2].

Genetic structure in Chamaecrista fasciculata and its association with phenotypic variation.

Quantifying population genetic structure is important to understanding evolutionary diversification within species. Genetic structure can arise from local adaptation or genetic drift when gene flow is restricted among isolated populations. Intraspecific phenotypic differences often accompany genetic diversification, although phenotypic variation can also reflect plasticity in the absence of restricted gene flow.  In this study, we sought to determine if genetic structure exists among populations of Chamaecrista fasciculata (Fabaceae) that are morphologically distinct in leaf and stem pubescence. Pubescence can be a deterrent to herbivores or aid in thermoregulation of plants, and therefore could be an adaptive trait in this species. Geographic structure in pubescence of this species in the Southeast, but not other areas of its distribution, suggests that this trait may be influenced by environmental conditions, but it is unclear whether this is due to genetic structure within the species or simply reflects phenotypic plasticity. We collected genotypic data for 14 microsatellite loci from samples in nine populations in Mississippi to evaluate genetic structure. Populations were also scored for leaf and stem pubescence. The percentage of polymorphic loci across populations was high (mean = 96%), and mean observed and expected heterozygosity were 0.482 and 0.509, respectively. There was little evidence of genetic structure across Mississippi. For example, an analysis of molecular variance based on physiographic regions, representing different soil conditions and plant communities, showed that most of the observed variation occurs within individuals (64%), followed by among individuals (24%), among populations (11%), and among physiographic regions (1%). Additionally, a low, non-significant correlation between genetic and geographic distance was found in a Mantel test. There is little support that phenotypic variation corresponds to genetic structure at these microsatellite loci either. These preliminary results suggest that there is not strong genetic structure in populations of C. fasciculata in Mississippi, which may reflect the high possibility of gene flow among populations. The lack of genetic divergence between populations with strong pubescence and those with little pubescence suggests that this trait may be plastic. Study of genetic variation in additional populations across the Southeast is on-going.

1 - Mississippi State University , Biological Sciences, Barr Ave, Mississippi State University, MS 39762, Starkville, Mississippi, 39762, United States
2 - Mississippi State University, Biological Sciences, PO Box GY, Starkville, MS, 39762, United States

Keywords:
genetic structure
Phenotypic variation
Chamaecrista fasciculata.

Presentation Type: Recent Topics Poster
Session: P, Recent Topics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM
Number: PRT005
Abstract ID:1173
Candidate for Awards:None