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Abstract Detail

Reproductive Processes

Greenberg, Kimberly [1], Levin, Rachel Ann [2], Miller, Jill S. [2].

Gender dimorphism, polyploidy, and evolutionary affinities of Lycium australe (Solanaceae).

Lycium australe (Solanaceae) is the only endemic Lycium species in Australia, with a large geographical distribution spanning four states across the southern parts of the country. Despite its prevalence, L. australe has not been thoroughly characterized regarding its evolutionary provenance. Interestingly, preliminary field observations also suggested that gender dimorphism may be present in this species. Within Lycium, gender dimorphism appears to have arisen multiple times, and polyploidy is tightly correlated with gender dimorphism, both within and among species. Thus, the primary goals of this study were to identify the closest relative(s) of L. australe and document gender dimorphism in this species. Additionally, given the established association between dimorphism and polyploidy within Lycium, we used flow cytometry to infer ploidy across the entire range of L. australe.
Phylogenetic relationships were inferred using traditional chloroplast and nuclear sequence data as well as Restriction-Site-Associated-DNA sequencing (RAD-seq). Although plastid data separates L. australe into two clades, nuclear and RAD-seq data support L. australe as monophyletic. In addition, RAD-seq data provide strong support for L. horridum, a southern African species, as the closest relative to L. australe, suggesting a single dispersal event from southern Africa to Australia. Across the range of L. australe, male, female, and hermaphroditic plants were identified based on floral measurements and the presence or absence of pollen. Specifically, individuals in one plastid lineage (restricted to Western Australia) are either male (lack style and stigma) or female (lack pollen) and are exclusively polyploid (either tetraploid or hexaploid). By contrast, individuals within the other plastid lineage (located throughout southern Australia) are either female or hermaphrodite and either diploid or polyploid. Thus, Lycium australe provides one of only two known exceptions to the correlation between gender dimorphism and polyploidy within the genus and serves as a valuable model for understanding the evolution of dimorphism in Lycium.

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1 - Amherst College, Biology, McGuire Life Sciences Building, Amherst, MA, 01002, USA
2 - Amherst College, Department Of Biology, McGuire Life Sciences Building, Amherst, MA, 01002, USA

gender dimorphism
male sterility

Presentation Type: Oral Paper
Session: 30, Reproductive Processes
Location: Fort Worth Ballroom 7/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 3:45 PM
Number: 30008
Abstract ID:243
Candidate for Awards:None

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