担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：The Royal Society  

It has long been suggested that dimorphic female-limited Batesian mimicry of two closely related Papilio butterflies, Papilio memnon and Papilio polytes, is controlled by supergenes. Whole-genome sequencing, genome-wide association studies and functional analyses have recently identified mimicry supergenes, including the doublesex (dsx) gene. Although supergenes of both the species are composed of highly divergent regions between mimetic and non-mimetic alleles and are located at the same chromosomal locus, they show critical differences in genomic architecture, particularly with or without an inversion: P . polytes has an inversion, but P . memnon does not. This review introduces and compares the detailed genomic structure of mimicry supergenes in two Papilio species, including gene composition, repetitive sequence composition, breakpoint/boundary site structure, chromosomal inversion and linkage disequilibrium. Expression patterns and functional analyses of the respective genes within or flanking the supergene suggest that dsx and other genes are involved in mimetic traits. In addition, structural comparison of the corresponding region for the mimicry supergene among further Papilio species suggests three scenarios for the evolution of the mimicry supergene between the two Papilio species. The structural features revealed in the Papilio mimicry supergene provide insight into the formation, maintenance and evolution of supergenes.

This article is part of the theme issue ‘Genomic architecture of supergenes: causes and evolutionary consequences’.

DOI： 10.1098/rstb.2021.0198

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その他リンク： https://royalsocietypublishing.org/doi/full-xml/10.1098/rstb.2021.0198

担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers Media SA  

Papilio butterflies are known to possess female-limited Batesian mimicry polymorphisms. In Papilio memnon, females have mimetic and non-mimetic forms, whereas males are monomorphic and non-mimetic. Mimetic females are characterized by color patterns and tails in the hindwing and yellow abdomens. Recently, an analysis of whole-genome sequences has shown that an approximately 160 kb region of chromosome 25 is responsible for mimicry and has high diversity between mimetic (A) and non-mimetic (a) alleles (highly diversified region: HDR). The HDR includes three genes, UXT, doublesex (dsx), and Nach-like, but the functions of these genes are unknown. Here, we investigated the function of dsx, a gene involved in sexual differentiation, which is expected to be functionally important for hindwing and abdominal mimetic traits in P. memnon. Expression analysis by reverse transcription quantitative PCR (RT-qPCR) and RNA sequencing showed that mimetic dsx (dsx-A) was highly expressed in the hindwings in the early pupal stage. In the abdomen, both dsx-A and dsx-a were highly expressed during the early pupal stage. When dsx was knocked down using small interfering RNAs (siRNAs) designed in the common region of dsx-A and dsx-a, a male-like pattern appeared on the hindwings of mimetic and non-mimetic females. Similarly, when dsx was knocked down in the abdomen, the yellow scales characteristic of mimetic females changed to black. Furthermore, when dsx-a was specifically knocked down, the color pattern of the hindwings changed, as in the case of dsx knockdown in non-mimetic females but not mimetic females. These results suggest that dsx-a is involved in color pattern formation on the hindwings of non-mimetic females, whereas dsx-A is involved in hindwing and abdominal mimetic traits. dsx was involved in abdominal and hindwing mimetic traits, but dsx expression patterns in the hindwing and abdomen were different, suggesting that different regulatory mechanisms may exist. Our study is the first to show that the same gene (dsx) regulates both the hindwing and abdominal mimetic traits. This is the first functional analysis of abdominal mimicry in butterflies.

DOI： 10.3389/finsc.2022.929518

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掲載種別：研究論文（学術雑誌）   出版者・発行元：American Association for the Advancement of Science (AAAS)  

In a Batesian mimic butterfly <italic>Papilio polytes</italic>, mimetic females resemble an unpalatable model, <italic>Pachliopta aristolochiae</italic>, but exhibit a different color pattern from nonmimetic females and males. In particular, the pale-yellow region on hind wings, which correspondingly sends important putative signals for mimicry and mate preference, is different in shape and chemical features between nonmimetic and mimetic morphs. Recently, we found that mimetic-type <italic>doublesex</italic> [<italic>dsx (H)</italic>] causes mimetic traits; however, the control of dimorphic pale-yellow colors remains unclear. Here, we revealed that <italic>dsx (H)</italic> switched the pale-yellow colors from UV-excited fluorescent type (nonmimetic) to UV-reflecting type (mimetic), by repressing the papiliochrome II synthesis genes and nanostructural changes in wing scales. Photoreceptor reactivities showed that some birds and butterflies could effectively recognize mimetic and nonmimetic pale-yellow colors, suggesting that a genetic switch in the UV response of pale-yellow colors may play essential roles in establishing the dimorphic female-limited Batesian mimicry.

DOI： 10.1126/sciadv.abd6475

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<title>Abstract</title>Dimorphic female-limited Batesian mimicry in the swallowtail butterfly <italic>Papilio polytes</italic> is regulated by the supergene locus <italic>H</italic>, harbouring the mimetic (<italic>H</italic>) and non-mimetic (<italic>h</italic>) <italic>doublesex</italic> (<italic>dsx</italic>) gene. In the present study, we demonstrated that <italic>dsx-H</italic> negatively affects the number of eggs laid, hatching rate, larval survival rate, and adult lifespan. When crossed with <italic>hh</italic> males, the number of eggs laid of mimetic females (genotype <italic>HH</italic>) was lower than that of non-mimetic females (<italic>hh</italic>). Moreover, <italic>hh</italic> and <italic>Hh</italic> females laid fewer eggs when crossed with <italic>HH</italic> males. The hatching and larval survival rates were lower when both female and male parents harboured <italic>dsx-H</italic>. The adult lifespan of <italic>HH</italic> females was shorter than that of <italic>hh</italic> females, while it was similar in males regardless of the genotype. These findings suggest the presence of a cost–benefit balance of Batesian mimicry, which is evolved to avoid predation but is accompanied by physiological deficits, in this species.

DOI： 10.1038/s41598-020-78055-1

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その他リンク： http://www.nature.com/articles/s41598-020-78055-1

担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.jinsphys.2018.02.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Association for the Advancement of Science (AAAS)  

Batesian mimicry protects animals from predators when mimics resemble distasteful models. The female-limited Batesian mimicry in Papilio butterflies is controlled by a supergene locus switching mimetic and nonmimetic forms. In Papilio polytes, recent studies revealed that a highly diversified region (HDR) containing doublesex (dsx-HDR) constitutes the supergene with dimorphic alleles and is likely maintained by a chromosomal inversion. In the closely related Papilio memnon, which exhibits a similar mimicry polymorphism, we performed whole-genome sequence analyses in 11 butterflies, which revealed a nearly identical dsx-HDR containing three genes (dsx, Nach-like, and UXT) with dimorphic sequences strictly associated with the mimetic/nonmimetic phenotypes. In addition, expression of these genes, except that of Nach-like in female hind wings, showed differences correlated with phenotype. The dimorphic dsx-HDR in P. memnon is maintained without a chromosomal inversion, suggesting that a separate mechanism causes and maintains allelic divergence in these genes. More abundant accumulation of transposable elements and repetitive sequences in the dsx-HDR than in other genomic regions may contribute to the suppression of chromosomal recombination. Gene trees for Dsx, Nach-like, and UXT indicated that mimetic alleles evolved independently in the two Papilio species. These results suggest that the genomic region involving the above three genes has repeatedly diverged so that two allelic sequences of this region function as developmental switches for mimicry polymorphism in the two Papilio species. The supergene structures revealed here suggest that independent evolutionary processes with different genetic mechanisms have led to parallel evolution of similar female-limited polymorphisms underlying Batesian mimicry in Papilio butterflies.

DOI： 10.1126/sciadv.aao5416

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担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1038/s41598-017-13419-8

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その他リンク： http://www.nature.com/articles/s41598-017-13419-8

担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Biology Centre, AS CR  

DOI： 10.14411/eje.2017.046

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

The female-limited Batesian mimicry polymorphism in Papilio butterflies is an intriguing system for investigating the mechanism of maintenance of genetic polymorphisms. In Papilio polytes, an autosomal region encompassing the sex-determinant gene doublesex controls female-limited mimicry polymorphism. In the closely related species P. memnon, which also exhibits female-limited Batesian mimicry polymorphism, we identified two allelic sequences of the doublesex gene that corresponded exactly with the mimetic and non-mimetic female phenotypes. Thus, the genetic basis of the mimicry polymorphism in P. memnon is similar to that in P. polytes. However, the mimetic and non-mimetic alleles of the two species were not identical, and the divergence of alleles occurred independently in P. memnon and P. polytes. Different mutation-selection processes may have resulted in the convergent patterns of mimicry polymorphism in these Papilio butterflies.

DOI： 10.1038/srep34782

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その他リンク： http://www.nature.com/articles/srep34782