At this step, viability selection will work against the trait selected in captivity.
Here we introduce a spatial model of evolution which assumes viability selection, mutations and random mating.
The MCT1rs1049434 genotype distribution (39.8 % AA, n = 69; 47.3 % AT, n = 82; 12.7 % TT, n = 22) was in Hardy-Weinberg equilibrium (P = 0.486) confirming no genotyping errors, population subdivision, viability selection, or systematic mating.
After migration, viability selection takes place.
Poor environmental conditions generate strong viability selection on egg size.
The life cycle consists of four steps: migration, viability selection, sexual selection, and reproduction.
Both increasing viability selection and decreasing migration reduce this threshold further (results not shown).
Linear increases in mutation probability with male age did not outweigh the effect of viability selection on male quality.
Once viability selection on colour is relaxed however, sexual selection can evolve in arbitrary directions in different populations [5].
Supporting a genetic basis, we did observe a large difference in viability selection on size between the isolated and tributary mainstem populations.
A second objective was to test whether brain size increased with age, as expected if there is viability selection against reduced brain size.
