Bumblebee Workers Show Differences in Allele-Specific DNA Methylation and Allele-Specific Expression

Area of Science:

• Genomics
• Epigenetics
• Insect Biology

Background:

• Allele-specific expression (ASE) is observed in Hymenopteran species, but its underlying molecular mechanisms are unclear.
• DNA methylation is a known regulator of ASE in mammals, and methylation systems exist in Hymenoptera.

Purpose of the Study:

• To investigate the relationship between DNA methylation and allele-specific expression in bumblebees (Bombus terrestris).
• To determine if DNA methylation directly drives genome-wide allele-specific expression in this species.

Main Methods:

• Utilized RNA-Sequencing (RNA-Seq) and whole-genome bisulfite sequencing (WGBS) data from reproductive and sterile bumblebee workers.
• Analyzed genome-wide allele-specific expression and allele-specific DNA methylation patterns.

Main Results:

• Identified widespread allele-specific expression and allele-specific DNA methylation in bumblebee workers.
• ASE patterns were largely consistent between reproductive and sterile workers and varied across colonies.
• Reproductive workers exhibited more allele-specific methylation than sterile workers.
• No significant overlap was found between genes with ASE and those with allele-specific methylation.

Conclusions:

• Cis-acting DNA methylation does not appear to be the primary driver of genome-wide allele-specific expression in Bombus terrestris.
• The mechanisms regulating ASE in Hymenoptera likely involve factors other than direct DNA methylation.
• Further research is needed to elucidate the precise molecular drivers of ASE in bumblebees.