Adaptation to contrasting habitats and heterozygosity-fitness correlations in eelgrass (Zostera marina).

Keil, Katharina (2011) Adaptation to contrasting habitats and heterozygosity-fitness correlations in eelgrass (Zostera marina). (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 112 pp.

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Eelgrass Zostera marina is an ecosystem-engineering species in coastal soft sediment habitats that lives in widely diverging habitats. I aimed to detect divergent selection and habitat adaptation comparing 3 pairs of permanently submerged versus intertidal populations using genome scans, a genetic marker based approach. 3 different statistical approaches for outlier identification revealed divergent selection at 6 loci among 46 markers (6 SNPs, 29 EST microsatellites and 11 anonymous microsatellites). These outlier loci were repeatedly detected in parallel habitat comparisons, suggesting the influence of habitat-specific selection. Functionally interesting loci were linked to genes involved in osmoregulation, water balance and reproductive processes. The identified outlier loci are valuable candidates for further investigation into the genetic basis of natural selection. I also aimed to investigate how fitness and multilocus heterozygosity (MLH) are related in Z. marina. Using 37 microsatellites, I assessed the correlation of fitness measured as clone size and MLH in two Z. marina populations from the Baltic Sea. I showed for the first time that the intermediate heterozygosity principle, stating that offspring from parents with an intermediate level of relatedness will be have the highest fitness, applies in a clonal plant. In ecosystems that are structured and maintained by only one species, like seagrass beds, heterozygosity represents an important component of genetic variation that has rarely been assessed before.

Document Type: Thesis (PhD/ Doctoral thesis)
Thesis Advisor: UNSPECIFIED
Keywords: Evolutionary Ecology of Marine Fishes; Ichthyology; habitat adaptation, seagrass, Zostera marina, genome scan, microsatellite, snp, eelgrass, subtidal, intertidal, heterozygosity, fitness, mlh
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EV Marine Evolutionary Ecology
Date Deposited: 23 Jun 2011 07:33
Last Modified: 06 Jul 2012 15:04

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