Neighboring genes shaping a single adaptive mimetic trait

Area of Science:

• Evolutionary biology
• Developmental genetics
• Animal coloration

Background:

• Heliconius butterflies exhibit striking mimicry, with similar wing patterns evolving independently in different species.
• Understanding the genetic basis of these convergent patterns is key to studying adaptation.

Purpose of the Study:

• To investigate the role of candidate genes in the development of red wing patterns in Heliconius melpomene and Heliconius erato.
• To identify genes responsible for convergent evolution of wing coloration.

Main Methods:

• Quantitative reverse transcription PCR (qRT-PCR) was used to profile gene expression.
• In situ hybridization was performed on developing butterfly wings.
• Expression patterns of three candidate genes in the red pattern locus were analyzed.

Main Results:

• Convergent gene expression domains for optix and kinesin were observed in both species.
• Optix expression correlated with all red wing elements.
• Kinesin expression was specifically linked to the red forewing band.

Conclusions:

• The genes optix and kinesin play a crucial role in generating convergent red wing patterns in Heliconius.
• These tightly linked genes likely act together as a "hotspot" for adaptive evolution.
• The findings provide insight into the genetic mechanisms underlying mimicry and adaptation.