Evolutionary and molecular studies of quantitative traits
Apart from blood samples for DNA analysis we have collected both morphological measurements (e.g. wing length, tarsus length, scull length and bill measurements) and data on life-history and fitness related traits (e.g. arrival day, egg measurements, breeding success). The population was mapped on a number of genetic markers resulting in a genetic linkage map that shows the relative order of the markers in the genome.
We are now working on refining the resolution of the genetic linkage map by adding more markers. We have used the genetic map together with pedigree information and individual genotypes and phenotypes to map qualitative trait loci (QTL). Wing length is a trait that is important both for fitness and migratory strategies in our great reed warblers. On chromosome 2, we have found a region that has major effect on wing length.
QTL mapping in wild populations can provide information on the genetic structure of ecologically interesting traits (e.g. how many genes are involved and their effect) and give an insight to how genetic variation is maintained in traits that are under selection.
Monitored since 1983
The population of great reed warblers at Lake Kvismaren was founded in 1978 and has been studied in detail every year since 1983. By using a large pedigree, and a linkage map covering 60% of the great reed warbler genome, we have found a quantitative trait loci (QTL) for wing length. Here, Maja Tarka with a great reed warbler at lake Kvismaren.
QTL-studies on unmanipulated, free living populations are so far rare and this is to our knowledge the first in a wild bird population. QTLs in wild populations are important to get a better understanding for genetic architecture in polygenic traits in natural environment and selection. Apart from giving us a better understanding of the microevolution of wing length in our great reed warbler population, it can also shed light on the adaptation of this trait in long versus short distance migrants.