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conference paper · ARPHA Conference Abstracts

Improving surveillance of Dacus frontalis through DNA barcoding and ortholog-based phylogenomics

In plain language

Dacus frontalis is an economically significant fruit fly distributed throughout Africa and intercepted within the European Union, making precise diagnostic tools critical for phytosanitary control and international agricultural trade. Genetic investigations show roughly four per cent divergence in the standard cytochrome c oxidase subunit I mitochondrial barcode region between North African and sub-Saharan populations. This marked intraspecific variation complicates routine identification. To address these challenges, researchers are broadening continental barcode coverage using Sanger sequencing and short-read genomic datasets. Additionally, an ortholog-based genomic workflow is under development using OMA standalone and Read2Tree to move beyond single-locus analysis. Although the phylogenomic workflow remains under development, current barcode analyses confirm two distinct mitochondrial lineages matching northern and sub-Saharan zones. Combining these approaches will establish a robust molecular framework for accurate species identification, origin tracing, and agricultural biosecurity.

Key takeaways

  • Populations of Dacus frontalis display approximately four per cent mitochondrial barcode divergence between North African and sub-Saharan regions.
  • High genetic variation within the species complicates standard identification procedures during agricultural surveillance.
  • Expanded mitochondrial barcoding and an ortholog-based genomic workflow are being integrated to resolve lineage structures.
  • The genomic workflow remains under development to test nuclear genome alignment and support future origin tracing.
  • Improved diagnostic tools aim to assist biosecurity authorities in Africa and importing regions such as the European Union.

Why it matters

Accurate pest identification is crucial for protecting agriculture and facilitating international trade. High genetic diversity in Dacus frontalis can cause misidentifications at border inspections, potentially allowing destructive fruit flies to enter new regions or leading to unnecessary trade restrictions. Establishing reliable molecular frameworks ensures early detection and origin tracing, strengthening phytosanitary surveillance across Africa and export destinations such as the European Union.

Commercialisation angle

This research could support diagnostic tools and origin-tracing services for phytosanitary inspection agencies, biosecurity regulators, and agricultural border authorities. The tools aim to improve routine testing and intercept pest movements along trade routes. However, the work represents early-stage development, as the ortholog-based genomic workflow is still being designed and expanded reference libraries are actively being compiled, meaning practical deployment within operational surveillance systems remains several development stages away.

AI-generated from the published abstract. Always read the original work before citing.

Abstract

Dacus frontalis is an economically important fruit fly widely distributed across Africa and already intercepted in the European Union, making reliable diagnostics essential for trade and phytosanitary surveillance. Recent coordinated sampling with African partner institutions revealed unusually high mitochondrial divergence in the cytochrome c oxidase subunit I (COI) barcode region, with approximately 4% divergence between North African and sub-Saharan populations. This level of intraspecific variation complicates routine identification and highlights the need for a geographically broader molecular reference framework, as well as complementary genomic tools able to resolve lineage structure and support future origin tracing. To improve diagnostic robustness, we are expanding continental COI coverage by generating new Sanger barcodes and by recovering mitochondrial barcode sequences from short-read genomic datasets. In parallel, we are developing an ortholog-based genomic workflow that combines OMA standalone for ortholog detection with Read2Tree for phylogenomic reconstruction. This framework is intended to move beyond single-locus inference and provide genome-wide resolution of differentiation patterns within D. frontalis . Current analyses based on COI consistently recover two well-differentiated mitochondrial lineages, broadly corresponding to northern and sub-Saharan sampling regions. Increasing barcode coverage is improving the representation of African populations and refining our interpretation of this divergence. The ortholog-based component is still under development, but it is expected to test whether the same structure is supported across the nuclear genome and to identify markers useful for future origin-tracing applications. Building an integrated molecular framework combining expanded COI coverage with an emerging ortholog-based genomic approach will strengthen diagnostic capacity for D. frontalis . By enabling more robust identification and providing a foundation for future origin tracing, this work supports early detection, surveillance, and phytosanitary preparedness in Africa and in regions at risk of introduction, including the European Union, where D. frontalis has already been detected in France and a single intercepted specimen was recorded in Belgium.

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DOI: 10.3897/aca.9.e204106

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