King, Ursula , Lopez Peredo, Elena , Les, Donald .
Isolation and characterization of microsatellite loci in Najas flexilis (Hydrocharitaceae) using 454 genome sequencing.
Najas flexilis (waternymph) is a monoecious, hydrophilous annual. Unlike many submerged aquatic plants it cannot reproduce vegetatively. Although circumboreal in distribution, N. flexilis is rare in the European portion of its range and is protected under European Union law. To date little genetic information has been available for this aquatic species. The objective of this work is to develop and characterize microsatellite markers for N. flexilis. Using 454 GS-FLX Titanium sequencing technology 110,358 sequence reads were obtained for N. flexilis, with microsatellite loci detected in 5563 of these reads. Primer pairs were designed to amplify 39 of these regions and 35 of these primers have successfully amplified in N. flexilis. To estimate genetic diversity, these markers have been tested on 21 accessions across the entire range of the species. In addition other Najas species have been assessed for cross-tranferability of these markers, including N. guadalupensis subsp. olivacea, the recently reported N. flexilis x N. guadalupensis hybrid, N. muenscheri, and N. marina. The majority of these markers were transferable and amplified successfully in the Najas species tested, with the exception of N. marina (the only dioecious species in this genus) where only two loci amplified. As a monoecious species, it has been assumed in the past that N. flexilis is outcrossing and therefore possesses high genetic diversity. However, our study has found extremely low genetic diversity in the microsatellite regions tested, even between transatlantic populations. Outcrossing is not guaranteed in monoecious species and low genetic diversity may result if much pollination occurs geitonogamously. Indeed there have been several conflicting reports on the spatial and temporal separation of flowering in N. flexilis. Another explanation for low diversity would be possible if N. flexilis were facultatively apomictic. Alternatively population genetic diversity could be intrinsically low due to vicinism or population bottlenecks. Studies currently are ongoing into the reproductive biology of this species to determine more accurately the breeding system involved.
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1 - Trinity College Dublin, Biology, Dublin, Ireland
2 - University Of Connecticut, Ecology & Evolutionary Biology, 75 N. Eagleville Road, Unit 3043, Storrs, CT, 06269-3043, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell C/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 4:15 PM