Miller, Allison , Bertram, Tracey , Romero-Hernandez, Carolina , Sampliner, Danielle , Dillman, Casey , Mendoza-Herrera, Azucena , Grauke, L.J. .
Chloroplast haplotype sharing across morphologically distinct taxa within North American Carya (pecans, hickories).
A central paradox of plant evolutionary biology is that trees exhibit rapid rates of microevolution while maintaining limited population structure and high rates of within-population variation. At the species level, these population-level observations may lead to morphologically distinct taxa that share haplotypes across species boundaries. In this study, we test the null hypothesis that chloroplast haplotypes are unique to morphologically distinct taxa within North American Carya (pecan, hickories). North American Carya are monophyletic and are classified into two sections: Section Apocarya includes four diploid species found in bottomland habitats, Sect. Carya includes diploid and tetraploid representatives found in both bottomland and upland habitats. Forty morphological observations were obtained from each of 690 herbarium specimens representing nine North American Carya species, and were analyzed using multivariate techniques. Four variable chloroplast spacers were sequenced for Carya and outgroups [rpL14-rpL36 (N = 52 individuals), atpB-rbcL (N = 88), trnL-rpL32F (N = 65), and ndhC-trnVx2 (N = 68)]. Within Carya, sequences for all regions were generated for 40 individuals. The combined aligned length was 3524 base pairs consisting of 88 variable sites organized into 15 haplotypes. Measures of variation for the four-region dataset are as follows: haplotype diversity = 0.741; Nucleotide diversity per site (Pi) = 0.00269, Theta-W per site = 0.00667. Approximately 1/3 of each dataset consisted of C. illinoinensis individuals (N = 16 – 27). At the intraspecific level, the number of haplotypes per region within C. illinoinensis ranged from two (atpB-rbcL) to six (rpL14-rpL36); when the data were combined (N = 16), eight distinct haplotypes were recovered within C. illinoinensis. Preliminary analyses suggest that chloroplast haplotypes are widely distributed among morphologically distinct Carya species. Interspecific gene flow in areas of sympatry, and/or incomplete lineage sorting in North American Carya lineages may account for these observations.
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1 - Saint Louis University, Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA
2 - Saint Louis University, Biology, Saint Louis, MO, 63103, USA
3 - Saint Louis University
4 - Saint Louis University, Biology, 3507 Laclede Avenue, St. Louis, MO, 63103
5 - Saint Louis University, Biology, 3507 Laclede Avenue, St. Louis, MO, 63103, USA
6 - United States Department of Agriculture - Agricultural Research Servic, National Clonal Germplasm Repository for Pecans and Hickories, Pecan Breeding & Genetics, 10200 FM 50 S, Somerville, TX, 77879, USA
7 - United States Department of Agriculture - Agricultural Research Servic, Pecan Breeding & Genetics, 10200 FM 50 S, Somerville, TX, 77879
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Alpine C/Snowbird Center
Date: Monday, July 27th, 2009
Time: 10:30 AM