PT  - JOURNAL ARTICLE
AU  - Linlin Zhang
AU  - Arnaud Martin
AU  - Michael W. Perry
AU  - Karin R.L. van der Burg
AU  - Yuji Matsuoka
AU  - Antónia Monteiro
AU  - Robert D. Reed
TI  - Genetic Basis of Melanin Pigmentation in Butterfly Wings
AID  - 10.1101/102632
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 102632
4099  - http://biorxiv.org/content/early/2017/02/07/102632.short
4100  - http://biorxiv.org/content/early/2017/02/07/102632.full
AB  - Despite the variety, prominence, and adaptive significance of butterfly wing patterns surprisingly little known about the genetic basis of wing color diversity. Even though there is intense interest in wing pattern evolution and development, the technical challenge of genetically manipulating butterflies has slowed efforts to functionally characterize color pattern development genes. To identify candidate wing pigmentation genes we used RNA-seq to characterize transcription across multiple stages of butterfly wing development, and between different color pattern elements, in the painted lady butterfly Vanessa cardui. This allowed us to pinpoint genes specifically associated with red and black pigment patterns. To test the functions of a subset of genes associated with presumptive melanin pigmentation we used CRISPR/Cas9 genome editing in four different butterfly genera. pale, Ddc, and yellow knockouts displayed reduction of melanin pigmentation, consistent with previous findings in other insects. Interestingly, however, yellow-d, ebony, and black knockouts revealed that these genes have localized effects on tuning the color of red, brown, and ochre pattern elements. These results point to previously undescribed mechanisms for modulating the color of specific wing pattern elements in butterflies, and provide an expanded portrait of the insect melanin pathway.