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Percorrer por autor "de Graaf, Dirk"

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  • Genetic Diversity of Detoxification Genes in 18 Honey Bee Subspecies
    Publication . Li, Fernanda; Barbosa, Daniela; Bashir, Sana; Moreira de Sá, Leandro; Yadró Garcia, Carlos A.; Rufino, José; Rosa-Fontana, Annelise; Verbinnen, Gilles; de Graaf, Dirk; de Smet, Lina; Taliadoros, Demetris; Webster, Matthew; Pinto, M. Alice; Henriques, Dora
    The honey bees (Apis mellifera) is a key pollinator that is exposed to a wide array of xenobiotics, both natural (plant allelochemicals) and synthetic (pesticides), while foraging or through contaminated food within the hive. These compounds have both lethal and sub-lethal effects, impairing foraging activity and negatively affecting bee development and colony health. Similar to other insects, honey bees rely on detoxification pathways to metabolise xenobiotics into less toxic or more readily excretable forms. This process is a key mechanism underlying insecticide resistance and is influenced by genetic variation. Therefore, investigating polymorphisms in detoxification-related genes is a promising approach to predict species-specific responses to pesticide exposure. Five major gene families are involved in xenobiotic detoxification: cytochrome P450 monooxygenases (CYPs), carboxyl/cholinesterases (CCEs), glutathione Stransferases (GSTs), ATP-binding cassette transporters (ABCs), and uridine 5′-diphospho-glucuronosyltransferases (UGTs). In this study, we examined the genomic detoxification inventory of over 1,600 individuals representing 18 A. mellifera subspecies representing the four main evolutionary lineages. For each lineage and subspecies, single-nucleotide polymorphism (SNP) loci were identified within these genes, allele frequency and FST (fixation index) were calculated. Additionally, all variants were annotated to assess their potential impact on protein function. Findings from this study have the potential to inform breeding and conservation strategies by identifying populations more vulnerable to chemical stressors, ultimately supporting honey bee health in changing environments.
    2025Documento de conferência Acesso aberto Ver mais
  • Human-mediated rapid evolutionary change in european honey bees
    Publication . Li, Fernanda; Taliadoros, Demetris; Costa, Maíra; Yadró Garcia, Carlos A.; Cunha, Larissa; Henriques, Dora; Martin-Hernandez, Raquel; de Graaf, Dirk; Webster, Matthew; Pinto, M. Alice
    In its vast distributional range, spanning Africa, Europe, the Middle East, and western Asia, the honey bee Apis mellifera diversified into 30 subspecies grouped into four major evolutionary lineages. Two of these lineages, M (western/northern European) and C (southeastern European), are parapatric in Europe. However, increasingly intensified queen trading is likely eroding the natural genetic boundaries and altering the continent’s diversity patterns. To evaluate the impact of this recent human-mediated gene flow, we conducted an unprecedented survey spanning 33 countries and sampling more than 1,300 colonies, including 139 from conservation apiaries of the M-lineage subspecies A. m. mellifera. We used a dual-marker approach combining the hypervariable mitochondrial tRNALeu–cox2 intergenic region with nuclear genome-wide single-nucleotide polymorphisms (SNPs). Both markers were highly concordant at the lineage level and European scale, showing that in the native area of M-lineage, which covers western and northern Europe, C-lineage ancestry is now predominant. This pattern is congruent with widespread commercial dissemination of C-lineage subspecies (A. m. carnica, A. m. ligustica), which is leading to introgressive hybridisation and, in many regions, to almost complete replacement of native subspecies. The exceptions to this trend are the Iberian Peninsula, Ireland, and conservation apiaries, which retain almost exclusively native M-lineage ancestry. Remarkably, even within the native C-lineage range in the Mediterranean and southeastern Europe, the Italian subspecies A.m. ligustica, the most widely favoured subspecies worldwide, shows worrying levels of introgression from its C-lineage neighbour A.m. carnica. Equally striking is the widespread presence of African-lineage mitotypes, whose routes of introduction remain unclear. Altogether, these findings raise serious concerns about the genetic integrity of native subspecies and the consequences of admixture for adaptation in a rapidly changing environment shaped by climate change and emerging parasites and pathogens. Further, these changes may affect the gene pools of wild A. mellifera populations, recently classified as Endangered by the IUCN.
    2025Documento de conferência Acesso aberto Ver mais