What is the mechanism of haploid-diploid sex determination in honeybees?
Males are produced from fertilized eggs and females from unfertilized eggs
Females are produced from fertilized eggs and males from unfertilized eggs
Both males and females are produced from fertilized eggs
Both males and females are produced from unfertilized eggs
The mechanism of haploid-diploid sex determination in honeybees is that females are produced from fertilized eggs and males are produced from unfertilized eggs. This means that the female honeybee has two sets of chromosomes (diploid), one from each parent, while the male honeybee has only one set of chromosomes (haploid) from its mother.
The reason for this unique sex determination mechanism in honeybees is due to the peculiar genetic system of their haplodiploid genome, which is different from the typical chromosomal sex determination mechanism found in most other organisms. In honeybees, the sex of the offspring is determined by the presence or absence of a particular allele called the complementary sex determiner (csd) gene, which is located on a single haploid locus in the genome.
If a female honeybee receives two different alleles of the csd gene, she develops into a diploid female. However, if a male honeybee receives only one allele of the csd gene, he develops into a haploid male. Therefore, the fertilized eggs that receive a single set of chromosomes from the mother but are devoid of the paternal chromosomes, develop into males.
In summary, honeybees exhibit haploid-diploid sex determination, where females are produced from fertilized eggs and males are produced from unfertilized eggs, and this is determined by the presence or absence of the complementary sex determiner (csd) gene in the haploid genome.
Option b is the correct answer.