Sex Determination in the Hymenoptera: George E. Heimpel, Jetske G. de Boer Annual Review of Entomology, Vol. 53: 209-230, 2008
- Haplodiploidy: A species trait in which females are diploid (2N chromosomes) and males are haploid (N chromosomes).
- Arrhenotoky: A type of haplodiploidy in which females develop from fertilized eggs and males develop from unfertilized eggs.
- Thelytoky: A species or population trait in which unfertilized females produce only daughters.
- Paternal Genome Elimination: A type of haplodiploidy in which both females and males develop from fertilized eggs, but individuals in which the paternal chromosome set is eliminated develop into males.
SUMMARY POINTS
- The dominant and presumably ancestral mode of sex determination in the Hymenoptera is Arrhenotokous.
- A gene called Complementary Sex Determiner (CSD) has been cloned in Honey Bees. Females (Workers and Queens) are heterozygous for this gene and have the diploid number of chromosmes (2N = 32 chromosomes); males (Drones) are either hemizygous for the gene (one copy) and develop into normal fertile males, they have the haploid number of chromososme (N = 16 chromosomes) or, they are homozygous, i.e., diploid for the gene (and genome, 2N = 32 chromosomes) and are destroyed by Workers soon after hatching. These males, if not destroyed, are sterile.
- Thelytoky and Paternal Genome Elimination has been reported in the Hymenoptera as well.