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Evolutionary dynamics of migration and breeding in wild birds: genetic architecture, sexual conflicts and evolutionary constraints

Författare:
Publiceringsår: 2012
Språk: Engelska
Sidor: 266
Dokumenttyp: Doktorsavhandling
Förlag: Department of Biology, Lund University

Sammanfattning

Our knowledge of the evolutionary potential of traits involved in different selective episodes, especially in natural populations, is still limited. This is true for questions such as the genetic basis and inheritance of traits, how natural and sexual selection acts on them, and how selective conflicts influence the evolutionary response to selection. In my thesis, I investigate these questions, using a long term study population of great reed warblers (Acrocephalus arundinaceus) with known pedigree, as a model system. I have focused on traits at the interface between migration and breeding and worked both in the field, the DNA lab and used powerful statistical tools in quantitative genetics and quantitative trait locus (QTL) mapping. Moreover, using new technology (geolocators), I describe full migratory paths showing a unique case of small songbirds flying rapidly (probably non-stop), over the Mediterranean Sea and the Sahara Desert, where after birds spread out to winter over a huge range covering the entire sub-Saharan West Africa to the Congo Basin in the east. Early spring arrival to the breeding site is decisive for breeding success in song birds. I found that arrival date is a heritable trait, with higher genetic variance in experienced (≥ 2 year old) as compared with inexperienced (1 year old) birds. Traits are not independent units which can constrain their evolution. However, I found no sign of a morphological ‘migratory syndrome’ (genetic correlations between migration traits) on the population level, and no evolutionary constraint acting through morphology on arrival date. Wing length was negatively correlated with arrival. I found a strong intralocus sexual conflict acting on wing length, where males are selected for long wings and females for short wings. Also I present a large-effect QTL for wing length located on chromosome 2, which recently has been confirmed in the zebra finch, suggesting its generality among birds. I also present a conceptual framework for the study of intralocus sexual conflict. An analysis of 13 traits suggested that traits within a population can be in very different stages of the conflict. I have also investigated potential evolutionary constraints through genetic correlations between traits in ten long-term study populations of wild birds and found evolutionary constraints on morphology, but mainly on current selection. Finally I investigate a potential source of genetic variation in a hybrid zone between great reed warblers and clamorous warblers (A. stentoreus). No sign of introgression was found, suggesting that hybrids are sterile or offspring inviable. These studies make an important contribution to our knowledge of evolutionary dynamics in the wild.

Disputation

2012-03-02
09:30
Blå Hallen, Ekologihuset, Lund
  • Jon Slate

Nyckelord

  • Biology and Life Sciences
  • quantitative genetics
  • heritability
  • intralocus sexual conflict
  • antagonistic selection
  • QTL
  • G-matrix
  • wing length
  • arrival date
  • migration
  • geolocator
  • bird
  • Acrocephalus arundinaceus

Övriga

  • Wild great reed warblers
  • QTL mapping in wild birds
  • Molecular Ecology and Evolution Lab
  • Bengt Hansson
  • Dennis Hasselquist
  • ISBN: 978-91-7473-270-2

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