Differential gene expression between developing queens and workers in the honey bee, Apis mellifera

Area of Science:

• Developmental Biology
• Molecular Genetics
• Entomology

Background:

• Polyphenisms, or alternative morphologies, are common in insects and arise from differential gene expression.
• Honey bee (Apis mellifera) castes (queen and worker) are a well-studied example of insect polyphenism.
• While hormonal regulation of honey bee caste determination is known, the proximate molecular mechanisms remain largely unelucidated.

Purpose of the Study:

• To employ a molecular-genetic approach to investigate queen- and worker-specific gene expression during honey bee development.
• To identify genes involved in the proximate molecular mechanisms of caste differentiation in honey bees.

Main Methods:

• Utilized a molecular-genetic strategy to analyze gene expression differences between honey bee castes.
• Identified and characterized differentially expressed genes between developing queens and workers.

Main Results:

• Numerous genes exhibit differential expression between honey bee queen and worker castes.
• Seven differentially expressed loci were identified, belonging to diverse evolutionary and functional groups.
• Two key loci were highlighted: one homologous to lipid-binding proteins (retinoic acid-binding) and another with an Ets family transcription factor domain.

Conclusions:

• Caste determination in honey bees involves the specific activation of genes in both queens and workers, challenging the notion of it being solely queen determination.
• The identified differentially expressed genes, including potential regulators like lipid-binding proteins and transcription factors, offer insights into the molecular basis of polyphenism.
• This study provides a foundation for understanding the downstream molecular pathways contributing to queen- and worker-specific development.