title: The dynamic DNA methylation cycle from egg to sperm in the honey bee Apis mellifera.
abstract: In honey bees (Apis mellifera), the epigenetic mark of DNA methylation is central to the developmental regulation of caste differentiation, but may also be involved in additional biological functions. In this study, we examine the whole genome methylation profiles of three stages of the haploid honey bee genome: unfertilised eggs, the adult drones that develop from these eggs and the sperm produced by these drones. These methylomes reveal distinct patterns of methylation. Eggs and sperm show 381 genes with significantly different CpG methylation patterns, with the vast majority being more methylated in eggs. Adult drones show greatly reduced levels of methylation across the genome when compared with both gamete samples. This suggests a dynamic cycle of methylation loss and gain through the development of the drone and during spermatogenesis. Although fluxes in methylation during embryogenesis may account for some of the differentially methylated sites, the distinct methylation patterns at some genes suggest parent-specific epigenetic marking in the gametes. Extensive germ line methylation of some genes possibly explains the lower-than-expected frequency of CpG sites in these genes. We discuss the potential developmental and evolutionary implications of methylation in eggs and sperm in this eusocial insect species.
authors.affiliation: Biology Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA Department of Biology, Amherst College, Amherst, MA 01002, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Drewell
authors.affiliation: Biology Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA.
authors.forename: Eliot C
authors.initials: EC
authors.lastname: Bush
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Remnant
authors.affiliation: Biology Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA.
authors.forename: Garrett T
authors.initials: GT
authors.lastname: Wong
authors.affiliation: Biology Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA.
authors.forename: Suzannah M
authors.initials: SM
authors.lastname: Beeler
authors.affiliation: Computer Science Department, Harvey Mudd College, 301 Platt Boulevard, Claremont, CA 91711, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Stringham
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Julianne
authors.initials: J
authors.lastname: Lim
authors.affiliation: Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, NSW 2006, Australia benjamin.oldroyd@sydney.edu.au.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Oldroyd
mesh_terms: D000818:Animals; D001483:Base Sequence; D001516:Bees / Q000502:physiology*; D005075:Biological Evolution; D018899:CpG Islands / Q000502:physiology; D019175:DNA Methylation / Q000502:physiology*; D005260:Female; D015723:Gene Library; D006608:Hierarchy, Social; D008297:Male; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013094:Spermatozoa / Q000378:metabolism*
keywords: Apis mellifera; DNA methylation; Epigenetic; Gametes; Imprinting