Sex Chromosomes and Sex Determination in Lepidoptera

Traut, Walther; Sahara, Ken; Marec, František

doi:10.1159/000111765

Cited by 161 publications

(198 citation statements)

References 174 publications

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“…In females, each nucleus displayed a conspicuous spherical heterochromatin body (Supplementary Figure S3e), representing the so-called sex chromatin (W chromatin), which is a characteristic trait in females of the majority of advanced Lepidoptera including Geometridae (Traut and Marec, 1996;Traut et al, 2007). In contrast, somatic polyploid nuclei of males displayed a uniform texture of chromatin grains without any heterochromatin (Supplementary Figure S3f).…”

Section: Cytogenetic Characteristicsmentioning

confidence: 99%

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Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

et al. 2012

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We have constructed a linkage map for the peppered moth (Biston betularia), the classical ecological genetics model of industrial melanism, aimed both at localizing the network of loci controlling melanism and making inferences about chromosome dynamics. The linkage map, which is based primarily on amplified fragment length polymorphisms (AFLPs) and genes, consists of 31 linkage groups (LGs; consistent with the karyotype). Comparison with the evolutionarily distant Bombyx mori suggests that the gene content of chromosomes is highly conserved. Gene order is conserved on the autosomes, but noticeably less so on the Z chromosome, as confirmed by physical mapping using bacterial artificial chromosome fluorescence in situ hybridization (BAC-FISH). Synteny mapping identified three pairs of B. betularia LGs (11/29, 23/30 and 24/31) as being orthologous to three B. mori chromosomes (11, 23 and 24, respectively). A similar finding in an outgroup moth (Plutella xylostella) indicates that the B. mori karyotype (n ¼ 28) is a phylogenetically derived state resulting from three chromosome fusions. As with other Lepidoptera, the B. betularia W chromosome consists largely of repetitive sequence, but exceptionally we found a W homolog of a Z-linked gene (laminin A), possibly resulting from ectopic recombination between the sex chromosomes. The B. betularia linkage map, featuring the network of known melanization genes, serves as a resource for melanism research in Lepidoptera. Moreover, its close resemblance to the ancestral lepidopteran karyotype (n ¼ 31) makes it a useful reference point for reconstructing chromosome dynamic events and ancestral genome architectures. Our study highlights the unusual evolutionary stability of lepidopteran autosomes; in contrast, higher rates of intrachromosomal rearrangements support a special role of the Z chromosome in adaptive evolution and speciation.

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Section: Cytogenetic Characteristicsmentioning

confidence: 99%

“…Females are the heterogametic sex in Lepidoptera, with most commonly a W/Z female, Z/Z male system (for deviations see Traut et al, 2007). The sex chromosomes stand out in female pachytene spreads by their heterochromatic appearance and produce hemizygous inheritance patterns.…”

Section: Introductionmentioning

confidence: 99%

Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

et al. 2012

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“…Sexual karyotype was investigated using a standard cytogenetic technique for visualizing female W chromatin (Traut et al, 2007). We assayed male and female phenotypes from selected lineages and as fully specified in the results.…”

Section: Cytogenetic Assaysmentioning

confidence: 99%

Incomplete offspring sex bias in Australian populations of the butterfly Eurema hecabe

et al. 2016

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Theory predicts unified sex ratios for most organisms, yet biases may be engendered by selfish genetic elements such as endosymbionts that kill or feminize individuals with male genotypes. Although rare, feminization is established for Wolbachiainfected Eurema butterflies. This paradigm is presently confined to islands in the southern Japanese archipelago, where feminized phenotypes produce viable all-daughter broods. Here, we characterize sex bias for E. hecabe in continental Australia. Starting with 186 wild-caught females, we reared 46000 F1-F3 progeny in pedigree designs that incorporated selective antibiotic treatments. F1 generations expressed a consistent bias across 2 years and populations that was driven by an~5% incidence of broods comprising ⩾ 80% daughters. Females from biased lineages continued to overproduce daughters over two generations of outcrossing to wild males. Treatment with antibiotics of differential strength influenced sex ratio only in biased lineages by inducing an equivalent incomplete degree of son overproduction. Brood sex ratios were nevertheless highly variable within lineages and across generations. Intriguingly, the cytogenetic signature of female karyotype was uniformly absent, even among phenotypic females in unbiased lineages. Molecular evidence supported the existence of a single Wolbachia strain at high prevalence, yet this was not clearly linked to brood sex bias. In sum, we establish an inherited, experimentally reversible tendency for incomplete offspring bias. Key features of our findings clearly depart from the Japanese feminization paradigm and highlight the potential for more subtle degrees of sex distortion in arthropods.

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“…The predicted inevitable decay of Y and W chromosomes has led to the idea that they are "born to be destroyed" (Steinemann and Steinemann 2005) and indeed these chromosomes are often dispensable [e.g., Lepidoptera (Traut et al 2008), nematodes (Bull 1983), Orthoptera (Castillo et al 2010), and Odonata (Kiauta 1969)]. Some groups, such as Coleoptera and Diptera, exhibit multiple independent losses of the Y chromosome (White 1977).…”

Section: Forces Promoting Y(w)-chromosome Degenerationmentioning

confidence: 99%

Estimating Tempo and Mode of Y Chromosome Turnover: Explaining Y Chromosome Loss With the Fragile Y Hypothesis

Blackmon

Demuth

2014

Genetics

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Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain phylogenetic breadth we therefore assembled a database of 4724 beetle species' karyotypes and found substantial variation in sex chromosome systems. We used the data to estimate rates of Y chromosome gain and loss across a phylogeny of 1126 taxa estimated from seven genes. Contrary to our initial expectations, we find that highly degenerated Y chromosomes of many members of the suborder Polyphaga are rarely lost, and that cases of Y chromosome loss are strongly associated with chiasmatic segregation during male meiosis. We propose the "fragile Y" hypothesis, that recurrent selection to reduce recombination between the X and Y chromosome leads to the evolution of a small pseudoautosomal region (PAR), which, in taxa that require XY chiasmata for proper segregation during meiosis, increases the probability of aneuploid gamete production, with Y chromosome loss. This hypothesis predicts that taxa that evolve achiasmatic segregation during male meiosis will rarely lose the Y chromosome. We discuss data from mammals, which are consistent with our prediction.

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Sex Chromosomes and Sex Determination in Lepidoptera

Cited by 161 publications

References 174 publications

Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

Linkage map of the peppered moth, Biston betularia (Lepidoptera, Geometridae): a model of industrial melanism

Incomplete offspring sex bias in Australian populations of the butterfly Eurema hecabe

Estimating Tempo and Mode of Y Chromosome Turnover: Explaining Y Chromosome Loss With the Fragile Y Hypothesis

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