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Genetic Modification of a Hox Locus Drives Mimetic Color Pattern Variation in a Highly Polymorphic Bumble Bee
Wanhu Yang1, Jixiang Cui1, Yuxin Chen1
1Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing 100193, China.
Molecular Biology and Evolution
|December 1, 2023
Summary
Genetic variation in bumble bees (Bombus breviceps) controls mimetic color patterns. A long noncoding RNA located between Hox genes likely drives the evolution of orange and black abdominal coloration, revealing distinct genetic routes for mimicry.
Area of Science:
- Evolutionary biology
- Genetics
- Developmental biology
Background:
- Müllerian mimicry is a key driver of adaptive phenotypic divergence and convergence.
- The genetic underpinnings of mimetic color variation in bumble bees remain largely unexplored.
- Bombus breviceps exhibits polymorphic abdominal setal color (orange to black) in South Asian Müllerian mimicry rings.
Purpose of the Study:
- To investigate the genetic basis of mimetic color pattern variation in Bombus breviceps.
- To identify the genetic locus and molecular mechanisms responsible for abdominal color dimorphism.
- To compare the genetic routes of color evolution in comimetic species.
Main Methods:
- Genetic crossing experiments to determine inheritance patterns of color phenotypes.
- Genome-wide association studies to pinpoint genetic loci associated with color variation.
- Gene expression analysis and RNA interference to assess the role of specific genes and noncoding RNAs.
- Comparative analysis of the identified locus in related mimetic species.
Main Results:
- Color dimorphism is controlled by a single Mendelian locus, with orange being dominant.
- A specific intergenic region between Hox genes abd-A and Abd-B is strongly associated with color variation.
- Differential expression of an intergenic long noncoding RNA (lncRNA) between abd-A and Abd-B appears to drive color differentiation.
- Comimetic species utilize different genetic pathways for similar color shifts, indicating convergent evolution via distinct mechanisms.
Conclusions:
- Hox gene regions are identified as genomic hotspots for bumble bee color pattern evolution.
- Pleiotropic developmental loci, like the identified lncRNA, can facilitate adaptive radiations.
- Mimetic convergence in bumble bees can be achieved through independent genetic innovations.
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