Faculty of Biology - Evolutionary Biology
 
 
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Evolutionary genetics

The field of evolutionary genetics is concerned with understanding evolutionary changes over relatively small time scales ('microevolution'). We are particularly interested in traits that are involved in sexual selection. Mate choice and intrasexual competition are the two key components of sexual selection and together constitute a driving force that contributes to biological diversity. Traits of interest include morphological ornaments (such as the 'Popeye arms' of Gomphocerus sibiricus), acoustic signals (such as insect song), behavioral traits (such as display behaviors) and fitness traits (such as laying dates in birds). We employ a range of methods that include pedigree analyses as well as molecular genetics techniques.

Quantitative genetics

Evolutionary geneticsImportant insight into evolution can be gained from rather simple data. One very powerful framework for doing so is called quantitative genetics. Two types of information are sufficient for predicting short-term evolution: data on the heritability of traits and data on the strength of selection. The two components can be estimated from data on phenotypes from related individuals and data on reproductive success. The correlation between trait values and reproductive success in a population allows estimating the strength of selection, while the similarity of phenotypes between relatives allows estimating the amount of genetic variation within a population. Heritable variation is required for evolutionary change to occur.

We are particularly interested in cases where evolution does not follow the predicted patterns. For example, the genetic architecture of heritable variation might constrain evolution if traits under directional selection are genetically correlated to traits under stabilizing selection. But populations might also fail to respond to apparent selection when selection is acting on the environmental component rather than the (genetically) heritable component of trait variation. On the other hand, apparent response to selection might also be sufficiently explained phenotypic plasticity, i.e. the ability of animals to adjust their phenotype to the current environment, without any need for genetics changes of allele frequencies in a population.

We are currently establishing a laboratory population of the Siberian Locust Gomphocerus sibiricus as a novel model system for studying the evolutionary genetics of sexual selection. The system holds great promise for addressing several questions related to sexual selection, coevolution and conflict. Most of the work is conducted in the laboratory, since laboratory conditions allow phenotyping of large numbers of individuals with known degrees of relatedness. Artificial breeding allows produced large numbers of half-siblings that are particularly informative for estimating quantitative genetic parameters. But we are also interested in testing our results under natural conditions. The feasibility of field as well as lab work makes the species particularly attractive for addressing questions of evolutionary questions.

 

 

 

Researchers involved:

Quantitative genetics in insects:
Holger Schielzeth
Anasuya Chakrabarty

Natural and sexual selection in grasshoppers:
Petra Dieker

Quantitative genetics in birds:
Tim Schmoll

Evolutionary genetics of sperm traits:
Steven Ramm
Bahar Patlar

Population genetics of bush crickets:
Lucienne Eweleit

Relevant publications

Schielzeth, H. & Husby, A. (2014). Challenges and prospects in genome-wide QTL mapping of standing genetic variation in natural populations. Annals of the New York Accademy of Sciences | DOI

Lehtovaara, A., Schielzeth, H., Flis, I. & Friberg, U. (2013). Heritability of lifespan is largely sex-limited in Drosophila. Am. Nat. 182: 653-665.

Husby, A., Schielzeth, H., Forstmeier, W., Gustafsson, L. & Qvarnström, A. (2013). Sex chromosome linked genetic variance and the evolution of sexual dimorphism of quantitative traits. Evolution 67: 609-619.

Forstmeier, W., Martin, K., Bolund, E., Schielzeth, H. & Kempenaers, B. (2011). Female exprapair mating behavior can evolve via indirect selection on males. Proceedings of the National Academy of Sciences 26: 10608-10613.