Search for dissertations about: "hybrid fitness"

Showing result 1 - 5 of 18 swedish dissertations containing the words hybrid fitness.

2. 1. Speciation - What Can be Learned from a Flycatcher Hybrid Zone?

   Author : Chris Wiley; Anna Qvarnström; Lars Gustafsson; Roger Butlin; Uppsala universitet; []
   Keywords : Biology; speciation; reinforcement; fitness; postzygotic isolation; asymmetrical hybridization; hybrid zone; species recognition; mate choice; sexual selection; direct benefits; parasite resistance; delayed plumage maturation; Ficedula hypoleuca; Ficedula albicollis; flycatcher; Biologi;

   Abstract : Studies of hybrid zones offer important insights into the process of speciation. Much of the knowledge to be gained is dependent on an accurate estimation of the strength of pre- and post-zygotic isolation between hybridizing taxa. My results demonstrate that hybridization can variously affect different components of fitness. READ MORE

4. 2. Natural and Sexual Selection in a Natural Hybrid Zone of Ficedula Flycatchers

   Author : Nina Svedin; Anna Qvarnström; Lars Gustafsson; Ian Owens; Uppsala universitet; []
   Keywords : Biology; postzygotic isolation; prezygotic isolation; asymmetrical isolation; sexual signals; hybrid fitness; co-existence; Biologi;

   Abstract : Speciation can be viewed as the formation of reproductive barriers between different populations. This thesis investigates patterns of natural and sexual selection shaping reproductive barriers between two hybridizing flycatchers (i.e. collared – and pied flycatchers). READ MORE

5. 3. Gene transfer by interspecific hybridization in bryophytes

   Author : Weerachon Sawangproh; Biodiversitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; homozygote; heterozygote; admixture; single nucleotide polymorphism; STRUCTURE; PCoA; hybrid index; inbreeding; outbreeding; hybrid depression; heterosis; phylogeny; purging selection; genetic purging; genotype; phenotype; sympatry; allopatry;

   Abstract : The role of hybridization in evolution has been debated for more than a century regarding bryophytes (mosses, liverworts, and hornworts) as well as most other organisms. Bryophytes have haplodiplontic life cycles with a dominant haploid generation. READ MORE

6. 4. Hybrid zone dynamics, assortative mating, and migratory programmes in a willow warbler migratory divide

   Author : Keith W. Larson; Susanne Åkesson; Staffan Bensch; Martin Schaefer; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; migratory divide; phenotype; willow warbler; hybrid zone; tension zone; Phylloscopus trochilus; migratype; assortative mating; migration; biology; biologi; evolutionär genetik; evolutionary genetics; migratory divide; phenotype; willow warbler; hybrid zone; tension zone; Phylloscopus trochilus; migratype; assortative mating; migration;

   Abstract : In this thesis I will compare and contrast the two willow warbler subspecies (Phylloscopus trochilus trochilus and P. t. acredula) with differing migratory phenotypes (or "migratype") in the context of their migratory divide and hybrid zone in central Sweden. Their migratory programs differ in the direction and distance traveled during migration. READ MORE

7. 5. Cis-regulatory variation and divergence in Capsella

   Author : Kim A. Steige; Tanja Slotte; Jeff J. Doyle; Uppsala universitet; []
   Keywords : Capsella; Shepherd s Purse; cis-regulatory changes; allele-specific expression; mating system shift; floral evolution; polyploidy; positive selection; purifying selection; transposable elements; small RNA; methylation; transposable element silencing; distribution of fitness effects;

   Abstract : Cis-regulatory changes in e.g. promoters or enhancers that affect the expression of a linked focal gene have long been thought to be important for adaptation. In this thesis, I investigate the selective importance and genomic correlates of cis-regulatory variation and divergence in the genus Capsella, using massively parallel sequencing data. READ MORE