Biology subjects

Alqassar, J. D.

Publications and source records attributed to Alqassar, J. D..

3 recordsLinked to original sources

bioRxiv2025

WntA expression and wing transcriptomics illuminate the evolution of stripe patterns in skipper butterflies

Skippers (Hesperiidae) form a distinct lineage of butterflies where the developmental mechanisms of color patterning have seldom been studied. The wing patterns of skippers often consist of median stripes, and classic comparative morphology studies suggest these elements are homologous to the Central Symmetry System (CSS) found in nymphalid butterflies. Consistent with this hypothesis, we show here that expression of the signaling ligand gene WntA, a marker of the CSS in nymphalids, prefigures the position of the main wing patterns of the silver-spotted skipper Epargyreus clarus. Notably, WntA expression is associated with different color outputs in the forewing vs. hindwing, validating a theory of pattern homology from the mid-twentieth century. To further gain insights into the genes associated with this patterning process, we generated an annotated genome for E. clarus and performed an RNAseq study profiling gene expression along the proximo-distal (P-D) axis of early pupal wings. These data suggest that the transcription factor genes lobe, u-shaped, and odd-paired are expressed in restricted P-D sections of the wing similarly to WntA, indicating they may participate in the patterning of the CSS. In addition, inverted expression patterns of dachsous and four-jointed, as well as the expression of transcription factors with roles in specifying proximal (homothorax, tiptop/teashirt) and distal (vestigial, scalloped) section of ths Drosophila wing disk, suggest a deep conservation of wing P-D patterning process between Diptera and Lepidoptera. This work highlights the developmental homology between the CSS of Hesperiidae and Nymphalidae, and enriches our knowledge of patterning mechanisms in lepidopteran wings. Summary StatementThis study reveals how skipper butterfly wing stripes share deep developmental origins with other butterflies, offering fresh insight into wing pattern evolution.

developmental biology↗

bioRxiv2025

Regionalization of gene expression and cell types in the silk gland of the pantry moth Plodia interpunctella

Lepidopteran silk glands include a posterior silk gland (PSG) that secretes core fibers and a middle silk gland (MSG) that secretes adhesive sericins. While well-studied in the silkworm (Bombyx mori), little is known about the gene expression profiles underlying the diversity of lepidopteran silks. Here we characterized the silk gland from the pantry moth Plodia interpunctella using a combination of quantitative and spatial assays. RNA-seq analyses of differential gene expression between the MSG and PSG depict the transcriptomic divergence between these two secretory tissues. In the PSG, high expression of fibroin genes FibL and FibH were detected, whereas MSG samples were dominated by transcripts encoding major sericins-- bioadhesive proteins that form the coating of the silk fiber. Hybridization Chain Reaction (HCR) mRNA profiling revealed sharp cellular boundaries within the silk gland: PSG cells exclusively expressed fibroins, while MSG comprised two compartments each expressing different combinations of sericins. Our findings corroborate the conserved organization of lepidopteran silk glands into specialized secretory subdivisions, and establish Plodia as a promising comparative model for studying silk diversity. This work provides a foundation for future research into the cellular and evolutionary basis of silk production across Lepidoptera.

genomics↗

bioRxiv2024

De Novo Genome Assembly and Annotation for the Webbing Clothes Moth (Tineola bisselliella): A Globally Distributed, Economically Important Pest

Tineola bisselliella, the webbing clothes moth, is an economically important, globally distributed synanthropic pest species and member of the basal moth lineage Tineidae. Tineola bisselliella is facultatively keratinophagous. Therefore, their larvae can cause extensive damage, particularly to clothing, textiles, and museum specimens. Despite the economic and phylogenetic importance of Tineola bisselliella, there is a lack of quality genomic resources for this species, or for others within the Tineidae family. The Tineola bisselliella genome presented here consists of 30 pseudochromosomes (29 autosomes and 1 Z chromosome) produced using synteny alignment to a closely related species, Tinea pellionella. The resulting final pseudochromosome-level assembly is 243.630 Mb and has an N50 length of 8.708 Mb. The assembly is highly contiguous and has similar or improved quality compared to other available Tineidae genomes, with 93.1% of lepidopteran orthologs complete and present. Annotation of the pseudochromosome-level genome assembly with the transcriptome we produced ultimately yielded 11,267 annotated genes. Synteny alignments between the Tineola bisselliella genome assembly and other Tineidae genomes found evidence for numerous small rearrangements with high synteny conservation. In contrast, synteny alignments performed between Tineola bisselliella and the more distantly related Bombyx mori and Melitea cinxia revealed more frequent small and large rearrangements as predicted by their evolutionary divergence. The reference quality annotated genome for Tineola bisselliella presented here will advance our understanding of the evolution of the lepidopteran karyotype by providing a chromosome-level genome for this basal moth lineage and provide future insights into the mechanisms underlying keratin digestion in Tineola bisselliella. Significance StatementTineola bisselliella, the webbing clothes moth, is a globally distributed synanthropic pest species that feeds on both keratin-based materials and detritus. This dietary habit can cause substantial damage to clothing, textiles, rugs, taxidermy, and museum specimens. In fact, keratinophagous organisms cause an estimated $1 billion worth of damage annually in the United States. However, the lack of a high-quality annotated reference genome for this basal moth species has thus far limited our understanding of the mechanisms underlying keratin digestion relevant to pest control efforts and has hampered efforts to investigate the broader phylogenetic relationships the Tineidae family necessary to reveal patterns of lepidopteran chromosome evolution. Here, we present the first reference quality genome for Tineola bisselliella and the first annotated genome for any member of the Tineidae family, providing a critical resource for the lepidopteran genomics and pest management communities.

genomics↗