ミツバチの運命を決める遺伝的綱引き(How a genetic tug-of-war decides the fate of a honey bee)

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2025-06-20 ペンシルベニア州立大学 (PennState)

ペンシルバニア州立大学の研究により、ミツバチのメス幼虫が女王蜂か働き蜂になるかは、父性・母性遺伝子の発現バランスによる“遺伝子の綱引き”で決まることが判明。発育初期192時間の間に、どちらの親由来遺伝子が優勢に働くかが個体の運命を左右する。人工授精による実験で、遺伝子インプリンティングが発育経路や生殖能力に影響することが示され、社会性昆虫における遺伝制御の重要な手がかりとなった。成果は『Genome Biology』誌に掲載。

<関連情報>

ミツバチ(Apis mellifera)における女王蜂と働き蜂のカースト決定における表現型の極端な可塑性に関連するゲノム内競合 Intragenomic conflict associated with extreme phenotypic plasticity in queen-worker caste determination in honey bees (Apis mellifera)

Sean T. Bresnahan,Shaun Mahony,Kate Anton,Brock Harpur & Christina M. Grozinger
Genome Biology  Published:18 June 2025
DOI:https://doi.org/10.1186/s13059-025-03628-0

ミツバチの運命を決める遺伝的綱引き(How a genetic tug-of-war decides the fate of a honey bee)

Abstract

Background

Caste determination of honey bees (Apis mellifera) exemplifies developmental plasticity, where differences in larval diet result in identical genotypes yielding either long-lived, reproductive queens or short-lived, facultatively sterile workers. Beyond environmental factors, intragenomic conflict between genes inherited from the mother (matrigenes) versus the father (patrigenes) is hypothesized to influence the underlying traits. In honey bees, the Kinship Theory of Intragenomic Conflict predicts selection on patrigenes to favor traits enhancing individual fitness, such as accelerated growth or increased body size—traits more active in queen-destined larvae. Although parent-of-origin effects have been reported in honey bees, the associated gene regulatory mechanisms remain unknown. While DNA methylation underlies parent-biased transcription in eutherians, angiosperms, and some insects, it is not operating in honey bees or other social insects.

Results

Allele-specific transcriptome analyses on queen- and worker-destined larvae at 192 h post-fertilization (hpf) reveal hundreds of genes with parent-of-origin effects, with queen-destined larvae showing overrepresentation of patrigene-biased transcription relative to worker-destined larvae. Genes with parent-biased transcription resemble imprinted genes in other taxa regarding genomic clustering, recombination rate, intron length, and CpG density, with a subset showing parent-biased transcription in 24 hpf eggs. Allele-specific ChIP-seq analyses demonstrate that parent-of-origin effects on caste-specific profiles of H3K27me3, H3K4me3, and H3K27ac are associated with parent-of-origin transcription.

Conclusions

These findings suggest that parent-of-origin intragenomic conflict may influence phenotypic plasticity and may be associated with histone post-translational modifications, suggesting a “noncanonical” genomic imprinting-like system in social insects.

細胞遺伝子工学
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