Systematics Section / ASPT
Levsen, Nicholas , Archibald, Jenny K. , Crawford, Daniel J. , Livers, Bridget , Mort, Mark E. , Samanta Roy, Debosree , Ryberg, Patricia E. , Santos-Guerra, Arnoldo .
Estimating allele frequencies and related statistics using dominant data, an empirical comparison with estimates using codominant data.
Codominant molecular markers offer a direct assessment of allelic variation in populations and thus, are the preferred means for determining gene diversity statistics. However, some characteristics of these markers restrict the extent of their use. For example, allozymes can show limited levels of variation, especially in recently diverged lineages, such as island endemics. While typically more variable than allozymes, characterizing microsatellites requires large investments of time and money and is particularly difficult in taxa that lack genome sequence data (i.e. non-model organisms). Because of this, a number of dominant markers (i.e. RAPD, AFLP, ISSR), which are more variable than allozymes but not as difficult to develop as microsatellites, are commonly employed to estimate levels of apportionment of genetic diversity and even reconstruct phylogeny among recently-derived taxa. However, because dominant markers cannot distinguish heterozygotes from dominant homozygotes, their use for calculating statistics like FST and expected heterozygosity requires an assumption of the level of within population inbreeding, which can produce inaccurate estimates. We used a Bayesian approach employed in Hickory v1.0.4 to estimate gene statistics (GST,FIS,hexp) from an extensive ISSR dataset for 15 populations of the Macronesian genus Tolpis (Asteraceae). The Bayesian gene statistic estimates are compared to values derived from allozyme studies of the same populations. To date only one study has tested the reliability of Hickory estimates empirically. As the use of ISSRs and other dominant data increases, it will be necessary to assess the robustness of using these data to estimate diversity; our analyses add to this knowledge and provide a robust comparison of these analytical methods.
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1 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
2 - University of Kansas, Department of Ecology & Evolutionary Biology, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
3 - Jardin de Aclimatacion de la Orotava, Calle Retama Numero 2, Puerto de la Cruz, Teneri, Canary Islands, E-38040, Spain
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM