Knowledge about sex determination in Lepidoptera is starting to unfold just over a decade after the discovery of the primary sex determination trigger in the silkworm Bombyx mori. The silkworm has a W-dominant sex determination mechanism with a PIWI-interacting RNA (piRNA) precursor gene called Feminizer (Fem) as the primary trigger. The emerging view is that the silkworm is unsuitable to predict primary triggers in other Lepidoptera species, despite its role as model organism. However, the Z-linked gene named Masculinizer (Masc), which is targeted by Fem piRNA in the silkworm, plays a key role in sex determination in all species studied so far. This conserved role of Masc at the beginning of the sex determination cascade differs from what is known in other insects, where the cascade is initially diverse and becomes increasingly conserved towards the end, where doublesex (dsx) is alternatively spliced into a female or male variant. Sex-specific dsx splicing is also conserved in Lepidoptera, while the other genes which make up the sex-determining cascade are yet to be revealed in full detail. The sex determination mechanisms in two species are highlighted because, unlike the silkworm, they do not rely on a primary trigger from the W chromosome. The moth Samia cynthia ricini uses the ratio of Z chromosomes to autosome sets to determine sex. The butterfly Bicyclus anynana has a sex determination more similar to the honey bee than to the silkworm, with the zygosity of a hypervariable region of Masc determining whether individuals become female or male.

• MeSH
• bourec genetika   MeSH
• hmyzí proteiny * metabolismus   genetika   MeSH
• motýli * genetika   fyziologie   MeSH
• můry * genetika   fyziologie   MeSH
• procesy určující pohlaví * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• hmyzí proteiny * MeSH

Many closely related species continue to hybridise after millions of generations of divergence. However, the extent to which current patterning in hybrid zones connects back to the speciation process remains unclear: does evidence for current multilocus barriers support the hypothesis of speciation due to multilocus divergence? We analyse whole-genome sequencing data to investigate the speciation history of the scarce swallowtails Iphiclidespodalirius and I . feisthamelii, which abut at a narrow ( ∼ 25 km) contact zone north of the Pyrenees. We first quantify the heterogeneity of effective migration rate under a model of isolation with migration, using genomes sampled across the range to identify long-term barriers to gene flow. Secondly, we investigate the recent ancestry of individuals from the hybrid zone using genome polarisation and estimate the coupling coefficient under a model of a multilocus barrier. We infer a low rate of long-term gene flow from I . feisthamelii into I . podalirius - the direction of which matches the admixture across the hybrid zone - and complete reproductive isolation across ≈ 33% of the genome. Our contrast of recent and long-term gene flow shows that regions of low recent hybridisation are indeed enriched for long-term barriers which maintain divergence between these hybridising sister species. This finding paves the way for future analysis of the evolution of reproductive isolation along the speciation continuum.

• MeSH
• fylogeneze MeSH
• genom hmyzu * MeSH
• genomika MeSH
• hybridizace genetická * MeSH
• motýli * genetika   klasifikace   MeSH
• reprodukční izolace MeSH
• sekvenování celého genomu MeSH
• tok genů * genetika   MeSH
• vznik druhů (genetika) MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Satellite DNAs (satDNAs) are abundant components of eukaryotic genomes, playing pivotal roles in chromosomal organization, genome stability, and evolution. Here, we combined cytogenetic and genomic methods to characterize the satDNAs in the genomes of Leptidea butterflies. Leptidea is characterized by the presence of a high heterochromatin content, large genomes, and extensive chromosomal reshuffling as well as the occurrence of cryptic species. We show that, in contrast to other Lepidoptera, satDNAs constitute a considerable proportion of Leptidea genomes, ranging between 4.11% and 11.05%. This amplification of satDNAs, together with the hyperactivity of transposable elements, contributes to the substantial genome expansion in Leptidea. Using chromosomal mapping, we show that, particularly LepSat01-100 and LepSat03-167 satDNAs, are preferentially localized in heterochromatin exhibiting variable distribution that may have contributed to the highly diverse karyotypes within the genus. The satDNAs also exhibit W-chromosome accumulation, suggesting their involvement in sex chromosome evolution. Our results provide insights into the dynamics of satDNAs in Lepidoptera genomes and highlight their role in genome expansion and chromosomal organization, which could influence the speciation process. The high proportion of repetitive DNAs in the genomes of Leptidea underscores the complex evolutionary dynamics revealing the interplay between repetitive DNAs and genomic architecture in the genus.

• Klíčová slova
• Lepidoptera, chromosome mapping, cryptic species, genome evolution, repetitive DNA,
• MeSH
• fylogeneze MeSH
• genom hmyzu * MeSH
• heterochromatin genetika   MeSH
• karyotyp * MeSH
• mapování chromozomů MeSH
• molekulární evoluce * MeSH
• motýli * genetika   MeSH
• satelitní DNA * genetika   MeSH
• transpozibilní elementy DNA MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• heterochromatin MeSH
• satelitní DNA * MeSH
• transpozibilní elementy DNA MeSH

Sex chromosomes play an outsized role in adaptation and speciation, and thus deserve particular attention in evolutionary genomics. In particular, fusions between sex chromosomes and autosomes can produce neo-sex chromosomes, which offer important insights into the evolutionary dynamics of sex chromosomes. Here, we investigate the evolutionary origin of the previously reported Danaus neo-sex chromosome within the tribe Danaini. We assembled and annotated genomes of Tirumala septentrionis (subtribe Danaina), Ideopsis similis (Amaurina), Idea leuconoe (Euploeina) and Lycorea halia (Itunina) and identified their Z-linked scaffolds. We found that the Danaus neo-sex chromosome resulting from the fusion between a Z chromosome and an autosome corresponding to the Melitaea cinxia chromosome (McChr) 21 arose in a common ancestor of Danaina, Amaurina and Euploina. We also identified two additional fusions as the W chromosome further fused with the synteny block McChr31 in I. similis and independent fusion occurred between ancestral Z chromosome and McChr12 in L. halia. We further tested a possible role of sexually antagonistic selection in sex chromosome turnover by analysing the genomic distribution of sex-biased genes in I. leuconoe and L. halia. The autosomes corresponding to McChr21 and McChr31 involved in the fusions are significantly enriched in female- and male-biased genes, respectively, which could have hypothetically facilitated fixation of the neo-sex chromosomes. This suggests a role of sexual antagonism in sex chromosome turnover in Lepidoptera. The neo-Z chromosomes of both I. leuconoe and L. halia appear fully compensated in somatic tissues, but the extent of dosage compensation for the ancestral Z varies across tissues and species.

• Klíčová slova
• butterflies, dosage compensation, fusions, sex chromosomes, sexual antagonism, sex‐biased genes,
• MeSH
• fylogeneze MeSH
• molekulární evoluce MeSH
• motýli * genetika   MeSH
• pohlavní chromozomy * genetika   MeSH
• syntenie MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Repetitive elements can cause large-scale chromosomal rearrangements, for example through ectopic recombination, potentially promoting reproductive isolation and speciation. Species with holocentric chromosomes, that lack a localized centromere, might be more likely to retain chromosomal rearrangements that lead to karyotype changes such as fusions and fissions. This is because chromosome segregation during cell division should be less affected than in organisms with a localized centromere. The relationships between repetitive elements and chromosomal rearrangements and how they may translate to patterns of speciation in holocentric organisms are though poorly understood. Here, we use a reference-free approach based on low-coverage short-read sequencing data to characterize the repeat landscape of two independently evolved holocentric groups: Erebia butterflies and Carex sedges. We consider both micro- and macro-evolutionary scales to investigate the repeat landscape differentiation between Erebia populations and the association between repeats and karyotype changes in a phylogenetic framework for both Erebia and Carex. At a micro-evolutionary scale, we found population differentiation in repeat landscape that increases with overall intraspecific genetic differentiation among four Erebia species. At a macro-evolutionary scale, we found indications for an association between repetitive elements and karyotype changes along both Erebia and Carex phylogenies. Altogether, our results suggest that repetitive elements are associated with the level of population differentiation and chromosomal rearrangements in holocentric clades and therefore likely play a role in adaptation and potentially species diversification.

• Klíčová slova
• Carex, Erebia, Lepidoptera, speciation, transposable elements,
• MeSH
• biologická evoluce MeSH
• Carex (rostlina) genetika   MeSH
• fylogeneze * MeSH
• karyotyp * MeSH
• molekulární evoluce MeSH
• motýli * genetika   MeSH
• populační genetika MeSH
• repetitivní sekvence nukleových kyselin genetika   MeSH
• vznik druhů (genetika) MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The complex of taxa closely related to Aricia anteros includes the species A. anteros sensu stricto, A. crassipuncta, A. bassoni, and A. vandarbani. All of them are sometimes considered as subspecies of a single polytypic species. Representatives of this complex are found in the Balkan Peninsula, Asia Minor, the Levant, the Caucasus, Transcaucasia, and Northern and Western Iran. In addition, an isolated population of A. anteros occurs in the Northern Black Sea region. In this work, based on DNA barcodes of all species and main populations of the complex, we show the existence of seven differentiated mitochondrial lineages: anteros (predominant in the Balkans), crassipuncta (predominant in Asia Minor), bassoni (the Levant), vandarbani (Talysh Mts), varicolor (Zagros Mts), dombaiensis (the Caucasus) and kalmius (Kalmius River basin in the Northern Black Sea region). The taxa of the A. anteros species complex are allopatric, except for A. anteros s.s. and A. crassipuncta, which have a mosaic distribution in eastern Anatolia and Transcaucasia. On the Balkan Peninsula, within the species A. anteros s.s, both the anteros and the crassipuncta mitochondrial haplogroups are found. This pattern is likely a consequence of interspecific hybridization and mitochondrial introgression. Based on mitochondrial DNA, the taxon A. crassipuncta mehmetcik from SE Anatolia is indistinguishable from A. crassipuncta crassipuncta, and the taxon varicolor from Central Iran is closer to the geographically distant European A. anteros than to the Anatolian A. crassipuncta. The geographically isolated and genetically differentiated population from the Kalmius River basin in the Northern Black Sea region is described here as a new subspecies.

• MeSH
• anatomické struktury zvířat anatomie a histologie   růst a vývoj   MeSH
• fylogeneze MeSH
• fylogeografie * MeSH
• motýli klasifikace   genetika   anatomie a histologie   MeSH
• rozšíření zvířat * MeSH
• taxonomické DNA čárové kódování * MeSH
• velikost orgánu MeSH
• velikost těla MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH

Nature has devised many ways of producing males and females. Here, we report on a previously undescribed mechanism for Lepidoptera that functions without a female-specific gene. The number of alleles or allele heterozygosity in a single Z-linked gene (BaMasc) is the primary sex-determining switch in Bicyclus anynana butterflies. Embryos carrying a single BaMasc allele develop into WZ (or Z0) females, those carrying two distinct alleles develop into ZZ males, while (ZZ) homozygotes initiate female development, have mismatched dosage compensation, and die as embryos. Consequently, selection against homozygotes has favored the evolution of spectacular allelic diversity: 205 different coding sequences of BaMasc were detected in a sample of 246 females. The structural similarity of a hypervariable region (HVR) in BaMasc to the HVR in Apis mellifera csd suggests molecular convergence between deeply diverged insect lineages. Our discovery of this primary switch highlights the fascinating diversity of sex-determining mechanisms and underlying evolutionary drivers.

• MeSH
• alely MeSH
• hmyzí proteiny genetika   metabolismus   MeSH
• homozygot MeSH
• motýli * genetika   MeSH
• procesy určující pohlaví * genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hmyzí proteiny MeSH

The world's largest butterfly genus Delias, commonly known as Jezebels, comprises ca. 251 species found throughout Asia, Australia, and Melanesia. Most species are endemic to islands in the Indo-Australian Archipelago or to New Guinea and nearby islands in Melanesia, and many species are restricted to montane habitats over 1200 m. We inferred an extensively sampled and well-supported molecular phylogeny of the group to better understand the spatial and temporal dimensions of its diversification. The remarkable diversity of Delias evolved in just ca. 15-16 Myr (crown age). The most recent common ancestor of a clade with most of the species dispersed out of New Guinea ca. 14 Mya, but at least six subsequently diverging lineages dispersed back to the island. Diversification was associated with frequent dispersal of lineages among the islands of the Indo-Australian Archipelago, and the divergence of sister taxa on a single landmass was rare and occurred only on the largest islands, most notably on New Guinea. We conclude that frequent inter-island dispersal during the Neogene-likely facilitated by frequent sea level change-sparked much diversification during that period. Many extant New Guinea lineages started diversifying 5 Mya, suggesting that orogeny facilitated their diversification. Our results largely agree with the most recently proposed species group classification system, and we use our large taxon sample to extend this system to all described species. Finally, we summarize recent insights to speculate how wing pattern evolution, mimicry, and sexual selection might also contribute to these butterflies' rapid speciation and diversification.

• Klíčová slova
• Aposematism, Biogeographic stochastic mapping, Divergence dating, Indo-Australian archipelago, Lepidoptera, Sequence capture,
• MeSH
• ekosystém MeSH
• fylogeneze MeSH
• motýli * genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Austrálie MeSH
• Nová Guinea MeSH

The molecular mechanisms of sex determination in moths and butterflies (Lepidoptera) with female heterogamety (WZ/ZZ) are poorly understood, except in the silkworm Bombyx mori. However, the Masculinizer (Masc) gene that controls male development and dosage compensation in B. mori, appears to be conserved in Lepidoptera, as its masculinizing function was recently confirmed in several moth species. In this work, we investigated the role of the Masc gene in sex determination of the codling moth Cydia pomonella (Tortricidae), a globally important pest of pome fruits and walnuts. The gene structure of the C. pomonella Masc ortholog, CpMasc, is similar to B. mori Masc. However, unlike B. mori, we identified 14 splice variants of CpMasc in the available transcriptomes. Subsequent screening for sex specificity and genetic variation using publicly available data and RT-PCR revealed three male-specific splice variants. Then qPCR analysis of these variants revealed sex-biased expression showing a peak only in early male embryos. Knockdown of CpMasc by RNAi during early embryogenesis resulted in a shift from male-to female-specific splicing of the C. pomonella doublesex (Cpdsx) gene, its downstream effector, in ZZ embryos, leading to a strongly female-biased sex ratio. These data clearly demonstrate that CpMasc functions as a masculinizing gene in the sex-determining cascade of C. pomonella. Our study also showed that CpMasc transcripts are provided maternally, as they were detected in unfertilized eggs after oviposition and in mature eggs dissected from virgin females. This finding is unique, as maternal provision of mRNA has rarely been studied in Lepidoptera.

• Klíčová slova
• Alternative splicing, Cydia pomonella, Lepidoptera, Masculinizer, Maternal provision of mRNA, Quantitative real-time PCR, RNA interference, Sex determination,
• MeSH
• bourec * genetika   MeSH
• kompenzace dávky (genetika) MeSH
• messenger RNA genetika   MeSH
• motýli * genetika   MeSH
• můry * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• messenger RNA MeSH

Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin ~100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants.

• MeSH
• biologická evoluce MeSH
• fylogeneze * MeSH
• motýli * genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH