Unravelling the genes forming the wing pattern supergene in the polymorphic butterfly Heliconius numata
|Author(s)||Saenko Suzanne, V1, Chouteau Mathieu2, Piron-Prunier Florence1, Blugeon Corinne3, Joron Mathieu4, Llaurens Violaine1|
|Affiliation(s)||1 : Sorbonne Univ, Inst Systemat Evolut & Biodiversite, UMR 7205, CNRS,MNHN,EPHE, CP50,57 Rue Cuvier, F-75005 Paris, France.
2 : Univ Guyane, LEEISA, USR 3456, CNRS Guyane, 275 Route Montabo, F-97334 Cayenne, French Guiana, France.
3 : PSL Univ Paris, Genom Facil, IBENS, Ecole Normale Super,CNRS,INSERM, F-75005 Paris, France.
4 : Univ Montpellier, Ecole Prat Hautes Etud, Ctr Ecol Fonct & Evolut, Univ Paul Valery,UMR CNRS 5175, F-34293 Montpellier 5, France.
|Source||Evodevo (2041-9139) (Bmc), 2019-08 , Vol. 10 , N. 1 , P. 16 (12p.)|
|WOS© Times Cited||17|
|Keyword(s)||Supergene, Wing pattern, Lepidoptera, Heliconius butterflies, Transcriptome, RNA sequencing, Gene expression|
Background Unravelling the genetic basis of polymorphic characters is central to our understanding of the origins and diversification of living organisms. Recently, supergenes have been implicated in a wide range of complex polymorphisms, from adaptive colouration in butterflies and fish to reproductive strategies in birds and plants. The concept of a supergene is now a hot topic in biology, and identification of its functional elements is needed to shed light on the evolution of highly divergent adaptive traits. Here, we apply different gene expression analyses to study the supergene P that controls polymorphism of mimetic wing colour patterns in the neotropical butterfly Heliconius numata. Results We performed de novo transcriptome assembly and differential expression analyses using high-throughput Illumina RNA sequencing on developing wing discs of different H. numata morphs. Within the P interval, 30 and 17 of the 191 transcripts were expressed differentially in prepupae and day-1 pupae, respectively. Among these is the gene cortex, known to play a role in wing pattern formation in Heliconius and other Lepidoptera. Our in situ hybridization experiments confirmed the relationship between cortex expression and adult wing patterns. Conclusions This study found the majority of genes in the P interval to be expressed in the developing wing discs during the critical stages of colour pattern formation, and detect drastic changes in expression patterns in multiple genes associated with structural variants. The patterns of expression of cortex only partially recapitulate the variation in adult phenotype, suggesting that the remaining phenotypic variation could be controlled by other genes within the P interval. Although functional studies on cortex are now needed to determine its exact developmental role, our results are in accordance with the classical supergene hypothesis, whereby several genes inherited together due to tight linkage control a major developmental switch.