An introduction to the csd locus and it's role in sex determining in the honeybee (Apis mellifera )

Currently, the sex in honeybees is determined by a mechanism known as the complementary sex-determiner (CSD), which has high diversity. Heterozygous individuals for the csd gene develop into females, while homozygotes develop into diploid males, which are removed by workers at the larval stage. Due to the high correlation of the genetic diversity of this locus with the number of diploid males and colony performance, many studies have been conducted on this region of genome. Fortunately, with advantage in genome sequencing technologies, the investigation of the csd gene conducted to molecular investigation and getting accurate information about this gene. Here, the history of sex determination in honeybees, the structure and diversity of csd gene and its association with the honeybee performance are considered.