Evolutionäre Mechanismen: MHC (major histocompatibility complex) und sein Beitrag zu sozialer Interaktion und Populationsaufspaltung während Speziationsprozessen
In preliminary investigations I have shown that Eurasian perch (<it>Perca fluviatilis</it> L.) of Lake Constance that form local aggregations with kin can olfactory discriminate between kin and non-kin, and additionally between the own and a foreign population that lives in sympatry within the same lake. Specific allelic compositions at MHC (major histocompatibility complex) genes have been shown to play a major role in kin recognition and to influence mate choice decisions in a variety of vertebrate species, including freshwater fishes, by affecting the individual body odour. In this project I want to investigate the role of MHC genes for kin- and population recognition. First, I will test if perch differentiate individuals by "family specific" MHC alleles learned by phenotype matching and use this information for kin recognition. Secondly I develop and test a new hypothesis that kin recognition could be the basal mechanism from which olfactory based population recognition may have derived. There I would show that in species using chemical communication for social interactions like e.g. kin recognition, MHC genes that determine specific odours could be under strong disruptive selection during the speciation process. This could lead to "population specific" MHC genes that can be used to olfactory discriminate between populations and drive reproductive isolation. Molecular genetic investigations about differences in the individual composition of specific MHC alleles within and between the coexisting perch populations of Lake Constance will be combined with behavioural experiments for MHC-mediated kin- and population recognition and mate choice strategies.
- FB Biologie
|(2006): Kin and population recognition in sympatric Lake Constance perch (Perca fluviatilis L.) : can assortative shoaling drive population divergence? Behavioral Ecology and Sociobiology. 2006, 59(4), pp. 461-468. ISSN 0340-5443. eISSN 1432-0762. Available under: doi: 10.1007/s00265-005-0070-3||
Kin and population recognition in sympatric Lake Constance perch (Perca fluviatilis L.) : can assortative shoaling drive population divergence?
Prior studies have shown that perch (Perca fluviatilis L.) of Lake Constance belong to two genetically different but sympatric populations and that local aggregations of juveniles and adults contain closely related kin. In this study, we analysed the genetic structure of pelagic perch larvae to investigate if kin-structured shoals already exist during early ontogenetic development or might be the result of homing to natal sites. Analysis of the gene frequencies at five microsatellite loci revealed that three out of five pelagic aggregations of larvae showed significant accumulation of kin. To investigate possible mechanisms of shoal formation, we tested if perch use olfactory cues to
|(2004): Postglacial colonization shows evidence for sympatric population splitting of Eurasian perch (Perca fluviatilis L.) in Lake Constance Molecular Ecology. 2004, 13(2), pp. 491-497. eISSN 1365-294X. Available under: doi: 10.1046/j.1365-294X.2003.02082.x||
Postglacial colonization shows evidence for sympatric population splitting of Eurasian perch (Perca fluviatilis L.) in Lake Constance
Previous microsatellite analysis showed that two subpopulations of perch (Perca fluviatilis L.) exist in Lake Constance. This raises questions of whether (i) Lake Constance was colonized by two populations that diverged in allopatry, or (ii) the two subpopulations diverged in sympatry. Sequence analysis of a 365 bp mtDNA fragment (5-end of the D-loop) of perch from Lake Constance and adjacent waters revealed 10 haplotypes. We suggest colonization via the Danube river, based on the frequency and dispersion of haplotypes, and knowledge of the lake s palaeohydrological development. Pairwise FST-values using mitochondrial DNA sequences showed no significant population subdivision. Our study provides strong evidence that subpopulations of perch in Lake Constance have diverged in sympatry.
|(2004): Evolutionary mechanisms of population divergence in Eurasian perch (Perca fluviatilis L.)||
The central issue of this thesis is the understanding of evolutionary mechanisms, that maintain and drive the divergence of populations and can lead to sympatric speciation. A former study showed that two populations of perch (Perca fluviatilis L.) co-exist in Lake Constance. For the first time I provide empirical evidence, that socially mediated divergence (kin- and population preference) in combination with ecological factors (difference in spawning times) could explain the origin and persistence of the perch subpopulations. Divergence between perch populations could be reinforced by reduced hybrid fitness.
|Laufzeit:||01.04.2006 – 31.03.2010|