Ease of fixation of a change in coiling: computer experiments on chirality in snails

摘要: This paper deals with chirality of snails. It explores the ease fixation a change in coiling direction, caused by an invasion snails carrying mutant allele into normal, homogeneous population, using Monte-Carlo simulation. Additionally, single-gene speciation on basis is discussed. Six factors are studied particular, namely: (i) absolute and relative population size; (ii) mating success, which known to be related shell shape, especially height/width ratio; (iii) maternal effect, underlying chirality; (iv) (low) mobility snails; (v) fitness differences (heterosis); (vi) invading being either dominant or recessive. The impact these quantified. Small populations not too few invaders dominance paramount relevance for its occasional fixation. In comparison this, effect turns out considerably less significant, whereas plays only minor role. simulations confirm expectation that heterosis can very effective. Logically, success also important factor. reflects observation nature among slender shells, when between mirror-image individuals still possible certain extent, reverse have originated far more frequently than globular where such matings impossible. Only latter cases, rare nature, may concern speciation.