DNA methylation is not a driver of gene expression reprogramming in young honey bee workers

Author(s)

Cardoso-Junior, Carlos A. M. ^{[1, 2]} ; Yagound, Boris ^[2] ; Ronai, Isobel ^[2] ; Remnant, Emily J. ^[2] ; Hartfelder, Klaus ^[1] ; Oldroyd, Benjamin P. ^{[2, 3]}

Affiliation

^[1] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Biol Celular & Bioagentes Patogen, Ribeirao Preto - Brazil

^[2] Univ Sydney, Sch Life & Environm Sci A12, Behav Ecol & Evolut BEE Lab, Ecol & Evolut, Sydney, NSW - Australia

^[3] Wissenschaftskolleg Berlin, Berlin - Germany

• Document type: Journal article
• Source: Molecular Ecology; v. 30, n. 19 AUG 2021.
• Web of Science Citations: 1

Abstract

The presence of DNA methylation marks within genic intervals, also called gene body methylation, is an evolutionarily-conserved epigenetic hallmark of animal and plant methylomes. In social insects, gene body methylation is thought to contribute to behavioural plasticity, for example between foragers and nurse workers, by modulating gene expression. However, recent studies have suggested that the majority of DNA methylation is sequence-specific, and therefore cannot act as a flexible mediator between environmental cues and gene expression. To address this paradox, we examined whole-genome methylation patterns in the brains and ovaries of young honey bee workers that had been subjected to divergent social contexts: the presence or absence of the queen. Although these social contexts are known to bring about extreme changes in behavioral and reproductive traits through differential gene expression, we found no significant differences between the methylomes of workers from queenright and queenless colonies. In contrast, thousands of regions were differentially methylated between colonies, and these differences were not associated with differential gene expression in the subset of genes examined. Methylation patterns were highly similar between brain and ovary tissues and only differed in nine regions. These results strongly indicate that DNA methylation is not a driver of differential gene expression between tissues or behavioral morphs. Finally, despite the lack of difference in methylation patterns, queen presence affected the expression of all four DNA methyltransferase genes, suggesting that these enzymes have roles beyond DNA methylation. Therefore, the functional role of DNA methylation in social insect genomes remains an open question. (AU)

• FAPESP's process: 16/15881-0 - Epigenetics and gene expression analysis of the longevity vs. reproduction trade-off in Apis mellifera L. (Apidae, Hymenoptera) queens
• Grantee: Carlos Antônio Mendes Cardoso Júnior
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/09269-3 - Methylome analysis of honey bee (Apis mellifera L.) worker ovaries in response to social condition
• Grantee: Carlos Antônio Mendes Cardoso Júnior
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 17/09128-0 - Molecular basis of the disruption in the reproduction-longevity trade-off syndrome in the social insect model organism Apis mellifera
• Grantee: Klaus Hartmann Hartfelder
• Support Opportunities: Regular Research Grants