Which two populations breed most frequently with one another? Population A Population B Population C Populations A and B most frequently breed because they both have a higher proportion of purple triangles and green circles, whereas population C has fewer triangles and circles. Populations A and B share more alleles (versions of the same gene) than they do with population C. High breeding levels will lead populations to share more of the same alleles and low breeding levels will lead populations to share fewer alleles, meaning that population C is more isolated, i.e. breeds less with populations A and B. The shapes ( ) represent different alleles or versions of the same gene.