Comparative genomics of the mimicry switch inPapilio dardanus

Abstract

The African Mocker Swallowtail, Papilio dardanus, is a textbook example in evolutionary genetics. Classical breeding experiments have shown that wing pattern variation in this polymorphic Batesian mimic is determined by the polyallelic H locus that controls a set of distinct mimetic phenotypes. Using bacterial artificial chromosome (BAC) sequencing, recombination analyses and comparative genomics, we show that H co-segregates with an interval of less than 500 kb that is collinear with two other Lepidoptera genomes and contains 24 genes, including the transcription factor genes engrailed (en) and invected (inv). H is located in a region of conserved gene order, which argues against any role for genomic translocations in the evolution of a hypothesized multi-gene mimicry locus. Natural populations of P. dardanus show significant associations of specific morphs with single nucleotide polymorphisms (SNPs), centred on en. In addition, SNP variation in the H region reveals evidence of non-neutral molecular evolution in the en gene alone. We find evidence for a duplication potentially driving physical constraints on recombination in the lamborni morph. Absence of perfect linkage disequilibrium between different genes in the other morphs suggests that H is limited to nucleotide positions in the regulatory and coding regions of en. Our results therefore support the hypothesis that a single gene underlies wing pattern variation in P. dardanus.

Behavioural mimicry in flight path of Batesian intraspecific polymorphic butterflyPapilio polytes

“…One aspect is its biological significance addressing whether the resemblance is actually in effect or not [1][2][3][4], and the other is the genetic basis that supports the resemblance. In the latter aspect, a 'supergene', a tightly linked cluster of loci on a chromosome, was hypothesized in butterflies [5,6], and the molecular architecture of the supergene has progressively been disclosed for Mü llerian [7][8][9][10][11] and Batesian mimicry [12][13][14].…”

Molecular Evolution: Breakthroughs and Mysteries in Batesian Mimicry

“…Instead, both new sets of sequence results suggest a multi-site supergene, with several mutations in a single large non-recombining gene, dsx. Strikingly, results from another mimetic butterfly, P. dardanus, also genetically mapped the mimicry locus to a region including no more than a few genes [5].…”

The Functional Basis of Wing Patterning inHeliconiusButterflies: The Molecules Behind Mimicry

“…It is hard to imagine that anyone in Bates' time actually "despised" the study of butterflies, and it is clear that this field has not yet risen to the esteemed position that Bates predicted. Yet butterflies, and their mimetic wing patterns in particular, have recently provided a wealth of insight into the genetic basis of adaptation (Joron et al 2011;Reed et al 2011;Heliconius Genome Consortium 2012;Martin et al 2012;Kunte et al 2014;Timmermans et al 2014). Animal pigmentation, more generally, has been a staple of research in genetics and evolutionary biology for over a century (Cott 1940;Bennett and Lamoreux 2003;True 2003;Hoekstra 2006;Kronforst et al 2012).…”