PhD Defense Seminar cum Oral Examination
The genetic basis of eyespot color pattern development in Bicyclus anynana butterflies
Speaker: Nesibe Özsu (Graduate Student Dept.of Biological Sciences, NUS)
Date: 19 January 2017, Thursday
Time: 10 am
Venue DBS Conference Room (S3 Level 5)
Supervisor: Assoc Prof Antonia Monteiro
All are welcome
Abstract – The origin of novel traits remains an outstanding question in evolutionary biology. In particular, it is largely unknown how these novel traits originate via modifications in development. Butterfly eyespots are complex novel traits that originated once, from simpler coloured spots, within the family Nymphalidae. Although several genes associated with eyespot development have been identified, the underlying gene regulatory network and function of eyespot genes still remains largely unknown.
Using a transcriptome analysis, I first identified 186 genes that were differentially expressed in wing tissues that develop eyespots in Bicyclus anynana compared to wing tissues that don’t. Many of these genes were involved in wound healing, suggesting that butterfly eyespots may have originated with the co-option of the wound healing gene regulatory network. Second, I investigated the genetic basis of eyespot number variation using an eyespot number mutant, Spotty, with two additional eyespots. Only a handful of the 461 genes that were differentially expressed between Spotty and wild-type butterflies overlapped with genes from the eyespot gene regulatory network, indicating possible targets for Spotty. Finally, I tested the function of wingless, a gene previously implicated in eyespot development, by down-regulating it in transgenic B. anynana butterflies via RNAi. Transgenic butterflies showed significant reductions in the size of eyespots and wings, compared to wild-type controls, indicating that wingless is a positive regulator of eyespot and wing development in B. anynana butterflies.