A specific breeding has been set up for this experiment and we obtained experimental mice from 15 breeding pairs.
Pure offspring of both populations (“German” GG and “French” FF) and reciprocal crosses between mice of the two populations (“mixed individuals”), either with a mother from the German and a father from the French population (GF) or with a mother from the French and a father from the German population (FG) have been bred.
Furthermore, female mice with a father from the German population had stronger selectivity than other mice.
A preference for some possible social partners over others can ultimately lead to mate choice. of the major histocompatibility complex, MHC), and proteins (e.g. Potential reasons for MHC being involved in mate discrimination are kin recognition and the enhancement of the offspring’s immune competence, which occurs by increasing either MHC diversity or dissimilarity by choosing a compatible mate .The evolution of mate choice is assumed to be driven by several mechanisms [ recognition of individuals, families, and populations is mainly regulated by two sensory systems: olfaction and vocalisation. An important pre-requisite for MHC-based mate choice in mice is the ability to identify and discriminate potential partners based on MHC alleles.All mice were kept and raised under standard conditions together with both parents until weaning at the age of four weeks.Female and male offspring were kept separated after weaning to ensure no sexual experience before the experiment.To explain this, we propose familial imprinting as the most probable process for information transfer from father to offspring during the offspring’s early phase of life, which possibly influences its future partner preferences.
Furthermore, our experiments show that preferences can change after the first day of encounter, which implies that extended observation times might be required to obtain results that allow a valid ecological interpretation.
We aimed to confirm the findings of preferences for paternally matching population backgrounds.
In order to do so we investigated three different aspects of mouse behaviour in our setup, (i) general activity of the focal mice, (ii) their degree of selectivity (i.e.
Examples of such study populations are two originally wild caught populations of ] studied the degree of mutual mate recognition according to population origin under semi-natural conditions and identified complex mating patterns in these two populations.
Assortative mating according to population background was only observed when mice of the single populations could get familiar with each other before individuals of both populations had the chance to meet.
In all mice, selectivity followed a clear temporal pattern: it was low in the beginning and reached its maximum only after a whole day in the experiment.