Fig. 4

Scheme of genotype diversity generation after multi-strain infection. Up: A honeybee is infected by an heterogeneous collection of N. ceranae spores in two possible ways: diploid or pseudodiploid spores may be heterozygous for a given marker (AB), and two or more different strains may be present in the infective group of spores (AB, and CD). Bottom: Most new formed spores may be fully asexual and hence show the same genotypes as above; however, after an hypothetical diploid stage and meiosis, homozygous spores are also formed (AA plus BB in one case, and CC plus DD in the other); additionally if two nuclei of different origin become included in a same spore, new genotypes would also appear (AC and so on). Without sexual reproduction, multi-strain infection could never produce AC, AD, BC or BD haplotypes