Question

Honey bees are haplodiploid, which means that the relatedness is, on average, expected to be 0.75 between:

• A. brother-brother pairs with the same parents.
• B. brother-sister pairs with the same parents.
• C. mated female-male pair.
• D. sister-sister pairs with the same parents.

Hint:

To calculate relatedness in haplodiploid systems: 1. Sisters share 100\% of paternal genes and 50\% of maternal genes, resulting in a total relatedness of 0.75.
2. Brothers share only maternal genes (r = 0.5), and brother-sister relatedness is 0.25.
3. Use haplodiploid genetics to explain eusocial behavior in bees.

Answer 1

The Correct Option is D

Step 1: Understand haplodiploidy in honey bees. Haplodiploidy is a sex-determination system where:
1. Males (drones) are haploid and develop from unfertilized eggs.
2. Females (workers and queens) are diploid and develop from fertilized eggs.
Sisters (workers) share: - 50\% of their genes from their mother (due to random assortment during meiosis). - 100\% of their genes from their haploid father (as all sperm from a haploid individual are identical). The total relatedness between sisters is: \[ r = 0.5 (from \ mother) + 0.5 \times 1 (from \ father) = 0.75 \] Step 2: Analyze relatedness in other pairings. Brother-brother pairs: Relatedness is 0.5, as they share the same haploid mother. Brother-sister pairs: Relatedness is 0.25, as the brother contributes no paternal genes. Mated female-male pair: Relatedness is 0, as unrelated individuals mate. Sister-sister pairs: Relatedness is 0.75, as calculated above. Step 3: Evaluate the options. Option (A): Incorrect. Brother-brother relatedness is 0.5. Option (B): Incorrect. Brother-sister relatedness is 0.25. Option (C): Incorrect. Mated female-male relatedness is 0. Option (D): Correct. Sister-sister relatedness is 0.75.