The work protocol.

Shown are two examples - Top panel: queen nr. 10.374, with a single infection; Bottom panel: queen nr. 10.179, with mixed-genotype infection. In each case, the infecting population was separated by FACS into clones and grown in microtiter plates (left). The clones (symbols: circles, squares) were then genotyped by five polymorphic microsatellite loci. Entries are the microsatellite alleles (lengths in bp) observed at each locus (C. bombi is diploid). Frequency indicates the number of clones of each type that were found in the infecting population. Note that the allelic pattern of the two “derived” genotypes suggests that nr.3 is a case of allele loss, and nr.4 is a case of recombination as a result of genetic exchange among the two upper genotypes that were considered “primary” due to their higher frequency.