In a haplodiploid mating system, how can the coefficient of relatedness between two sisters be 0.75 (75%)? Females are haploid, and they pass on 100% of their genes, whereas males are diploid and pass on 50% of their genes, meaning that the coefficient of relatedness is 0.75. Females can reproduce asexually, meaning they produce clones, and those clones share on average 75% of the genes of their sisters. If a queen mates with a single drone, then all the resulting females have all of the same genetic contribution from the male, since males are haploid and contribute 100% of their genes. Male and female bees are both diploid. The males contribute 100% of their genes to their offspring, and females contribute 50%. Therefore, each female offspring shares 75% of her genes with her sister siblings on average.

If a queen mates with a single drone, then all the resulting females have all of the same genetic contribution from the male, since males are haploid and contribute 100% of their genes

Explanation:

Haplodiploidy is a type of sex-determination system where males are haploid (i.e., they contain only a set of chromosomes 'n') and develop from unfertilized eggs, whereas females are diploid (i.e., they contain two complete sets of chromosomes '2n') and develop from fertilized eggs. The bees show this haplodiploid system of sex determination, which is quite common to many hymenopterans. In bees, workers and queens are diploid (2n) females and contain 32 chromosomes, a set of 16 chromosomes is contributed by the queen's egg, and another set of 16 chromosomes is contributed by the drone sperm (16 + 16 = 32 chromosomes). On the other hand, drones are haploid (n) males and contain only one set of 16 chromosomes, which is exclusively contributed by the queen's egg.