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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Phenotypic and Genetic Differentiation Between Sex Chromosome Races of Rumex hastatulus (Polygonaceae)

Simpson, Andrew 07 July 2014 (has links)
Wind-pollinated plants often have little genetic structure owing to high gene flow. However, sex chromosomes evolution promotes divergence, potentially leading to population subdivision. Rumex hastatulus (Polygonaceae) is a wind-pollinated, dioecious coloniser of open disturbed land with two sex chromosome races (SCRs), which occupy different parts of the species’ range in the southern USA. My thesis investigated phenotypic and genetic differentiation between the SCRs, based on a study of 28 populations sampled throughout the range. A glasshouse experiment demonstrated significant differentiation between the SCRs in several life-history traits, several of which exhibited clinal variation. Analysis of population genetic structure, based on 13 nuclear loci, revealed two distinct clusters corresponding to the two SCRs, with an estimated origin of the North Carolina SCR from the Texas SCR between ~5000–15000 generations ago. My results indicate that the SCRs have developed a moderate degree of phenotypic and genetic differentiation despite ongoing gene flow.

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