Adaptive introgression across species boundaries in Heliconius butterflies.
It is widely documented that hybridisation occurs between many closely related species, but the importance of introgression in adaptive evolution remains unclear, especially in animals. Here, we have examined the role of introgressive hybridisation in transferring adaptations between mimetic Heliconius butterflies, taking advantage of the recent identification of a gene regulating red wing patterns in this genus. By sequencing regions both linked and unlinked to the red colour locus, we found a region that displays an almost perfect genotype by phenotype association across four species, H. melpomene, H. cydno, H. timareta, and H. heurippa. This particular segment is located 70 kb downstream of the red colour specification gene optix, and coalescent analysis indicates repeated introgression of adaptive alleles from H. melpomene into the H. cydno species clade. Our analytical methods complement recent genome scale data for the same region and suggest adaptive introgression has a crucial role in generating adaptive wing colour diversity in this group of butterflies.
Department of Zoology, University of Cambridge, Cambridge, United Kingdom. cp419@cam.ac.uk
Carolina
C
Pardo-Diaz
Camilo
C
Salazar
Simon W
SW
Baxter
Claire
C
Merot
Wilsea
W
Figueiredo-Ready
Mathieu
M
Joron
W Owen
WO
McMillan
Chris D
CD
Jiggins
D000220:Adaptation, Biological; D000818:Animals; D005075:Biological Evolution; D002080:Butterflies / Q000235:genetics*; D049810:Genetic Speciation; D049750:Genome, Insect; D005838:Genotype; D006824:Hybridization, Genetic; D010641:Phenotype; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D060047:Reproductive Isolation; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014921:Wings, Animal / Q000033:anatomy & histology