Investigating red Malpighian tubules, a Candidate Gene for Red Pigmentation in Sulphur Butterflies and the Milkweed Bug

Pterin pigmentation is an important element of insect colouration. Pterins have been linked to predator avoidance and sexual selection as they are often bright yellow, orange, and red pigments. Despite the breadth of insects using pterin pigments for myriad functions the complete pterin metabolic pathway remains elusive. In this thesis, I describe my investigation of the gene, red Malpighian tubules, a candidate for the yellow to orange colouration switch in Colias butterflies. I find that in CRISPR knockouts of red in Colias eurytheme, mutant phenotypes display a loss of pterin pigmentation rather than a shift from red to yellow pigmentation. In RNAi experiments with Oncopeltus fasciatus I find that knockdowns of red result in a lighter abdominal colouration in 1st instar nymphs and a lightening of eye pigmentation in adults. These results suggest red may play a role in pterinosome formation rather than metabolizing a yellow pigment to red as initially thought.

Author

• Francescutti, Caroline Maria

Language

• en

Keyword

• Pieridae
• CRISPR
• Hemiptera
• Pterin
• RNAi
• Pigmentation

Date created

• 2021

Type of Work

• Master's Thesis

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Biological Sciences

Degree

• M.S.

Advisor

• Martin, Arnaud

Committee Member(s)

• Mappes, Johanna
• Manier, Mollie

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/c534fp67b