A fundus-centric view of myopia

The seemingly innocuous, easily remediable symptom of myopia—blurred distance vision—belies an insidious reality: myopia predisposes the eye to a range of sight-threatening diseases, including, but not limited to, pathologic myopia (PM) and retinal detachment. With a rapidly rising prevalence where half of humanity is predicted to be myopic by 2050, we are witnessing not just the emergence of a bespectacled generation, but also an increasing burden of irreversible visual impairment caused by myopia-related diseases. My PhD focuses on two important knowledge gaps. First, the epidemiology of PM has never been systematically investigated in the UK. To address this, I estimated the prevalence of PM using a random sample of mid-life adults with high myopia (spherical equivalent refraction ≤ -5D) from the population-based UK Biobank cohort. The results revealed a prevalence of 41.7%—with most cases being relatively mild (diffuse chorioretinal atrophy); however, the age-related and progressive nature of PM means an elevated risk of irreversible visual impairment for those affected later in life. Second, existing clinical predictors of the risks of myopia-related diseases—notably spherical equivalent refraction (SER) and axial length (AL)—do not provide personalised information about the anatomy of the posterior eye. This limitation partly explains why, despite both metrics being strong predictors at the population level, substantial variations in individual risks remain uncaptured. In myopia, an excessive enlargement of the globe puts significant stress on (or stretches) important structures in the posterior segment, which may explain the increased susceptibility to diseases affecting the posterior eye. To address the second gap, I argue for a ‘fundus-centric’ view of myopia: the characterisation of myopia at a more anatomically relevant fundus level using computational methods—as a supplement to conventional on-axis (along the visual axis) descriptors of myopia (SER and AL). The underlying premise is that fundus imaging offers a valuable first approximation of the degree of ocular stretching in an individual eye, thus providing personalised information about the risks of myopia-related diseases. I first investigated how fundus features varied across a broad spectrum of SER in healthy eyes from 23,000 adults in the UK Biobank. A wide range of fundus features were found to vary non-linearly as SER progressed from hyperopia to myopia: the optic disc became larger, less circular and orientated with its superior pole tilting towards the fovea; the disc-fovea distance increased; the vasculature became less tortuous with decreased branching complexity; and the vascular arcades curved more inwardly towards the fovea. In myopia, these changes appeared to be exponential—consistent with the known exponential increase in the risks of PM and retinal detachment with increasing myopia. In another study, I observed an increase in neuroretinal rim pallor with decreasing SER, with the temporal horizontal/inferior rim exhibiting the steepest rate of increase—consistent with the expectation that the papillomacular nerve fibre bundle, linked to the temporal rim, is particularly susceptible to damage from ocular stretching due to its straighter course. Importantly, I found evidence indicating that fundus imaging reflected differences in posterior eye shape, even when SER, age and sex were held constant. These findings support the premise that fundus imaging contains information—beyond what is available from on-axis descriptor of myopia alone—about ocular changes that may collectively be relevant to risk stratification. This culminated in the development of a deep learning-based metric—fundus refraction offset (FRO)—intended as a summary of how ‘anatomically myopic’ a fundus appears. A more negative FRO value indicated a more ‘myopic looking’ fundus than typical for an eye with the same SER. In the first (cross-sectional) validation study, I found evidence that FRO reflected differences in macular thickness and choroidal vascularity index, both derived from optical coherence tomography, even after controlling for AL or SER, as well as age, sex and ethnicity. In the second (longitudinal) validation study, a more negative baseline FRO was found to be associated with an increased risk of retinal detachment or breaks over 12 years, even among individuals with similar baseline SER (AL information not available), age, sex, macular thickness and history of cataract surgery. To conclude, myopia severity can be further quantified at the fundus level: such a ‘fundus-centric’ view of myopia allows the risks of complications to be captured at a level more personalised than is currently achievable using on-axis descriptors

Landscapes of anxiety between the cave and the oil palm trees: local legitimation in East Kalimantan

This thesis examines the intersection between international environmental governance initiatives for social forestry, smallholder palm oil cultivation, local struggles for land access, and the politics of indigeneity and citizenship in a changing Indonesian political economy. It uses a combination of discourse analysis and ethnography, guided by theoretical lenses of assemblage thinking and institutional bricolage, to interrogate two distinct types of land legitimation struggle practiced by members of Merabu village, located in the Berau District in East Kalimantan; one for social forestry and one for smallholder palm oil cultivation. It considers how land legitimation practices occur in contexts of the institutional pluralism and ambiguity in ways that aim to render some land claimants and their claims legitimate, allowable, and/or legal, and others not. Summary of findings suggest that practices of local land legitimation in Merabu involve productions of collective identity, social relations, and technologies of recognition in ways that render some actors, interests, and land claims legitimate and others subaltern, representing potential issues of injustice and alienation occurring through environmental governance practice. Villager strategies for repurposing assets and powers from one land rights context to another in attempts to render legally ambiguous claims legitimate reflect everyday struggles for citizenship in a democratizing Indonesia. This raises critical questions for how land rights, legality, and political subjectivity may be better understood within the contexts of environmental governance and Indonesian democracy in regards to the pursuit of justice. Analysis is guided by three core research questions: 1)How are contemporary local land struggles contextualized within neo-colonial histories of racialized socio-spatial control and their contestation? 2)How do environmental governance projects shape some local subjectivities, interests, and land use practices as legitimate and others illegitimate? 3)In what ways are denials of legitimacy contested and resisted by local land claimants in the pursuit of their interests and political inclusion? Following conceptual frameworks introduced in Chapter 2, and case study context in Chapter 3, I address these questions in my empirical chapters. To answer the first question, in Chapter 4, I conduct a deliberative discourse analysis on land policy texts and their political/historical contexts to trace how contestations over authoritative ways of conceptualizing land legitimacy shape productions of forest dwelling subjectivities as legitimate or illegitimate vis-à-vis land rights and political participation. Findings show that histories of contestation between multiple policy storylines of land legitimation affect systematic forms of alienation and subalternity for forest dwelling people, like the Lebbo. These alienations shape struggles for legitimation in contemporary contexts of environmental governance, wherein pluralist authoritative institutions and discourses of rights recognition interpellate forest-dwelling subjectivities in ambiguous and problematic ways. I answer the second question in Chapter 5, where I conduct ethnographic fieldwork in Berau over the course of 12 months in 2015-2016 to examine how the Berau Forest Carbon Project (BFCP), a subnational REDD+ demonstration project, worked to territorialize Merabu subjects and spaces within the REDD+ environmental governance assemblage at the project’s early stage. Findings suggest that essentializations of villager identities and interests draw on tropes of indigeneity while simultaneously denying formal indigenous rights or self-determination. Subject productions as such, combined with facilitation of capacities for legibility by State authorities, render villagers and their land claims to their ancestral forest legitimate insofar as they adhere to what Li calls the “non-market slot” (2014). I answer the third question in Chapter 6, where I draw on key-informant interviews collected during fieldwork in 2022, at the end of the BFCP project cycle, to examine villagers’ efforts to legitimate land claims for smallholder palm oil cultivation, i.e. outside the “non-market slot”. Here, I observe villagers repurpose technologies of legitimation gained through their participation in the BFCP for deployment in other contested legitimation claims with district government authorities in order to render themselves and the claims legitimate in what would otherwise be considered a restricted form of land use, in what I characterize as acts of bricolage. Here, I draw on insights from previous chapters and critical scholarship on citizenship in post-colonial Indonesia to argue that such legitimation practices in legally ambiguous contexts represent vital struggles for everyday citizenship amidst the incomplete project of Indonesian democratization. I my summation, I reflect on the fluid, reflexive relationship between indigeneity and citizenship in the Indonesian context in relation to the political ambitions of historically marginalized people in pursuit of autonomy, survival, and development

The three pillars of DJing authenticity: a sociological investigation of amateur DJing practices in Hong Kong 2019-2022

Acknowledging that sociological discourses surrounding club culture and DJing primarily look at its culture via a subcultural perspective, this dissertation dedicates its focus on live DJ sets, which are considered the process and product of musical production of DJing, and the socio-musical nature of authenticity in DJs’ delivery of the sets. It explores the notion of authenticity in the world of amateur DJing in Hong Kong, focusing on three interrelated pillars: presentational, conventional, and personal/political authenticity. Presentational authenticity refers to the DJ’s ability to cultivate an atmosphere of spontaneity and immersion by presenting themselves as improvisers who connect with their audiences. Conventional authenticity involves demonstrating competence and credibility within the shared conventions of the DJing world, including technical proficiency and adherence to stylistic expectations. Personal/political authenticity captures the DJ’s individual artistic voice and integrity, which is shaped by their lived experiences in the broader socio-political context. Drawing on interviews with 36 DJs and observations of live and online performances, the study shows how these forms of authenticity intersect in delivering live DJ sets. Primarily adopting an interactionist lens with respect to Becker’s (2008[1982]) art world perspective and Goffman’s (2021[1959]) dramaturgical approach, presentational authenticity and conventional authenticity are scrutinised based on the interactions within the world of amateur DJing. Lahire’s (2011) concept of the plurality of dispositions is also addressed to examine how DJs negotiate competing socio-musical expectations to curate performances that reflect their dispositions across multiple social fields, thereby displaying personal/political authenticity. By situating the study period in 2019-2022, when Hong Kong went through an extensive period of socio-political turmoil created by the 2019 Anti-ELAB movement and the COVID-19 pandemic, this study argues that the sense of DJing authenticity displayed should be positioned as dynamic, situational, and deeply embedded in the city’s evolving socio-political landscape. DJs emerge as cultural curators who not only mix music but also articulate identity, memory, and resistance through their performances, making authenticity a reflection of both personal trajectory and collective experience

The story of the three bloods: the effect of coagulation on drying blood droplets

In order to pursue criminals as quickly and efficiently as possible, forensic analysts must glean a wealth of information from a limited set of evidence in a short amount of time. This research aims to expand the information acquired from a crime scene by increasing understanding of blood drying behavior. Blood is a mixture of biological colloids and proteins, the drying of which has been examined for some time. These experiments overwhelmingly use anticoagulants such as EDTA and tri-sodium citrate to extend the lifetime and transportability of the blood by preventing coagulation, making it easier to perform laboratory experiments. While experiments using anticoagulated blood produce useful information for personalised medicine, they may be of limited relevance for the typical crime scene. To extend the usefulness of blood droplet research to reallife crime scenes where coagulation naturally occurs, fresh blood coagulation and a coagulation-like process utilised by the medical community for clotting assays were introduced to small whole blood droplets. Gravimetrics, optical coherence tomography, and image analysis of drying time-lapses for various geometries were used to examine three major areas: evaporation dynamics, cracking patterns, and substrate adhesion. Experiments found important differences in the delamination, internal dynamics, and final morphology of the droplets which may impact forensic conclusions, though the drying time and evaporation rate were found to be identical across all treatments

Building the Resilience and Prosperity of Pastoralists and Dryland Communities: Summary report of the research and policy dialogue, Nairobi, Kenya, 1–2 October 2025

Involving development partners and investors, governments, civil society actors, pastoral associations, policy and research organizations, this two-day dialogue on ‘Building the Resilience and Prosperity of Pastoralists and Dryland Communities’ was convened by three research for policy and practice institutions: the IGAD Centre for Pastoral Areas and Livestock Development (ICPALD), the Jameel Observatory for Food Security Early Action, and the Supporting Pastoralism and Agriculture in Recurrent and Protracted Crises (SPARC) programme. The conference offered a mix of sessions with presentations, plenary and panel discussions, space for audience interaction and showcased case studies, findings and good practices. Together, the sessions were designed to highlight: 1) pathways to prosperity and resilience for drylands and pastoralists; 2) advancing dryland’s futures through innovation and technology; and 3) investing in and delivering for dryland people

Chemical design and biological applications of fluorescence lifetime dyes and sensors

Fluorescent probes are proved to be one of the most powerful tools in the past decades, including detecting, quantifying, and visualizing of various molecular interactions and biological processes. However, most of the probes are based on fluorescent intensity as readouts, which are limited for sensitivity and challenge of spectral overlap. Alternatively, fluorescence lifetime (FLT) and fluorescence lifetime imaging microscopy (FLIM) provide time-resolved measurements. FLT is particularly well-suited for monitoring environmental changes because it is independent of concentration but can be sensitive to ion concentration, pH, and temperature etc. It can also be a sensitive tool to trace the interaction between proteins or sensors and analytes due to the shift of FLTs after binding behaviour. Moreover, unlike traditional fluorescence probes, FLT-based probes are better suited for multiplexed imaging due to the addition of the time-resolved dimension. Based on these, we successfully designed new FLIM probes which have good brightness and suitable FLT ranges and tried to answer biological questions using FLT as readouts. In this thesis, we have developed a new chemical library of dyes tailored for FLIM. These dyes either have different core structures or are conjugated with various side chains. We proved that changing of the side chains resulted in different brightness, water solubility and FLT (within the range of 5-25 ns). Additionally, these probes are quite stable and do not undergo photobleaching, which indicates their potential in imaging. Using this innovative FLIM toolbox, we explored FLT variations in different solution conditions, such as the conditions with reactive oxygen and nitrogen species (ROS/RNS). Moreover, we investigated FLT changes associated with DNA binding and DNA oxidative damage in cancer cell lines, providing valuable insights into FLIM probes as sensors for cellular oxidative stress and its broader implications, including their potential role in chronic neuropathic pain, which is associated with DNA oxidative damage. We further enhanced the selectivity of our designed dyes by conjugating them with peptides (e.g., antimicrobial peptides (AMPs)) and small inhibitors. The FLIM settings were optimized, and images reflecting FLTs were acquired. Data analysis of FLT was also refined to enhance accuracy and reliability. We have demonstrated the FLIM probes designed are conjugatable with peptides and small drugs, and achieved selectively targeting and obtained different readouts in different microenvironments. We also partially achieved multiplexing with this toolbox, shedding light on future real-time tracking of dynamic activities in cells

Regulation of human brown adipose tissue activity

The rising prevalence of obesity globally poses significant morbidity and mortality, as obesity increases the risk of developing a number of diseases such as diabetes, hypertension and cardiovascular disease. While some more recent interventions to treat obesity have been efficacious, they can cause undesirable side effects, highlighting a need for novel treatment options. Adipose tissue comprises brown (BAT) and white adipose tissue (WAT). WAT mainly stores energy, while BAT increases energy expenditure primarily through cold-induced thermogenesis, which is mediated through a specialised thermogenic protein, called uncoupling protein 1 (UCP1). Due to its role in thermogenesis, BAT has gained significant interest as a target to treat obesity and associated cardiometabolic disease. 2-deoxy-2- [¹⁸F]fluoro-D-glucose (¹⁸F-FDG) positron emission tomography (PET) is the most commonly used technique to quantify human BAT mass and activity, exploiting the substantial glucose uptake by BAT as a surrogate marker for BAT thermogenesis. The prevalence of detectable BAT at room temperature using ¹⁸F-FDG PET is reduced in individuals with increased cardiovascular risk such as obesity, diabetes and hypertension. However, ¹⁸F-FDG uptake by BAT may be confounded by obesity-induced insulin resistance so it remains unclear whether BAT thermogenesis is decreased in obesity and cardiometabolic disease. Our understanding of the regulation of human BAT activation also remains limited. Using transcriptomics, we recently identified serotonin as a potential regulator of human BAT, by demonstrating that the gene SLC6A4, which encodes the serotonin reuptake transporter (SERT), was one of the most differentially expressed genes in human brown compared with white adipocytes. SERT inhibition, which increases serotonin receptor activation, decreased human brown adipocyte thermogenesis. However, it is unknown whether serotonin levels are altered in obesity or if reduction in peripheral serotonin activity can lead to a therapeutic benefit. We hypothesised that (1) UCP1 expression in human BAT, a marker of BAT thermogenic capacity, is inversely associated with cardiovascular risk factors, (2) circulating and adipose tissue serotonin levels are increased in obesity and (3) inhibition of peripheral serotonin synthesis stimulates human BAT activity. To assess hypothesis 1, we measured UCP1 mRNA expression in whole adipose tissue (n=53) and in differentiated pre-adipocytes (n=85) from paired BAT and WAT biopsy samples obtained from patients undergoing elective neck surgery. UCP1 expression in BAT (but not in WAT or in differentiated brown or white pre-adipocytes) was inversely associated with obesity, ageing, insulin resistance and hypertension. Age was the only independent predictor of high UCP1 expression in BAT and obesity reduced the frequency of high UCP1 expression only in individuals >40 years. To explore the effect of obesity in young adults in vivo, ¹⁸F-FDG PET-MR scans were performed in young obese and age-matched normal weight individuals (n=6 in each weight group, mean age ~22 years) following 2 hours of mild cold exposure. Consistent with the UCP1 data, young individuals with obesity had preserved ¹⁸F-FDG uptake by BAT, despite increased insulin resistance. To determine if obesity alters peripheral serotonin levels, we measured circulating and abdominal adipose tissue serotonin concentrations in healthy age-matched individuals with normal body weight and obesity (n=10 in each weight group) during warm and cold exposure. The majority of circulating serotonin is inactive due to being platelet-bound with only a small proportion circulating freely. Platelet serotonin concentrations increased during cold exposure in normal weight individuals. However, in obese volunteers, inactive platelet serotonin levels increased during warm conditions, which dropped during cold exposure, accompanied by an increase in adipose tissue serotonin levels. These variations in serotonin concentrations suggest a potential dysregulation in cold-induced serotonin response in obesity. To assess whether inhibition of peripheral serotonin synthesis altered BAT activity, we undertook a double-blind crossover study in 8 healthy normal weight subjects and 8 participants with obesity. These volunteers were given placebo and telotristat ethyl tablets (an inhibitor of peripheral serotonin synthesis) for 2 weeks in random order. Telotristat ethyl reduced ¹⁸F-FDG uptake by BAT, increased total cholesterol levels and suppressed the rise in noradrenaline and insulin levels following cold exposure and oral glucose load respectively. In conclusion, UCP1 expression in BAT is reduced with ageing, obesity and cardiometabolic disease, in keeping with BAT dysfunctio

The ‘layered time’ of xenophobia and racial capitalism: comparing the everyday challenges and identities of African migrant women in Johannesburg and London

The literatures on xenophobia and its violence in post-apartheid South Africa and post-Brexit UK, while each providing a deep and important contextual analysis, lacks a broader examination of the everyday manifestations of anti-foreigner discrimination for different groups. Particularly, they lack the perspectives of African migrant women. Using a relationally comparative approach, this interdisciplinary study examines both the conceptual and context-specific literature on xenophobia and its relationship to racism in South Africa and the UK, drawing on primary qualitative, ethnographic and creative fieldwork with Congolese and Zimbabwean women in Johannesburg and London using both an intersectional and temporal lens. Comparing contexts, concepts and lived experiences, this study embeds African migrant women’s experiences of discrimination over time within scholarship, policy and practice. Theoretically, it contributes towards an expanded conceptual understanding of xenophobia in three ways. Firstly, by examining its relationship to racism in wider literature and specifically within the Congolese and Zimbabwean migrant literatures in both contexts, arguing for it to be conceptually understood as embedded within racism and as a form of structural discrimination. It then goes onto argue for xenophobia and racism to be grounded within a global and contextually specific understanding of racial capitalism. Secondly, by applying a framework of ‘layered time’ to the lived experience of xenophobia, to reveal the longer-term psychological and ontological effects of this multi-faceted form of discrimination on women migrants’ livelihoods and wellbeing. Thirdly, by analysing barriers to access for African migrant women in everyday areas of education, work, healthcare and housing through an intersectional lens. This analysis reveals that to attempt an accurate portrayal of women’s lives and to inform legal and rights-based responses, intersectional research must include not only how lives and livelihoods are affected by their multiple overlapping categories of structural identity, but also by individual choice, background and social networks. Calling for a transnational, temporal and racially capitalist analysis of xenophobia, this study emphasises the importance of exploring the mundane ‘everyday’ as well as sporadic eruptions of violence. It warns against the tendency to homogenise the lived experiences of African migrant women, highlighting the need to recognise their human complexities

Using serious leisure theory to explore the experiences of people walking the Camino

This study aims to investigate the differences in flow experiences between individuals walking alone and those walking with companions along the Camino de Santiago in Spain. The researcher conducted fieldwork in Arzúa, Spain, collecting both questionnaires and implementing interviews directly along the pilgrimage route. A mixed-methods approach was used, dividing participants into two groups: those walking alone and those walking with companions. Quantitative data were collected using the Flow State Questionnaire, with ANOVA and U-tests employed to determine if there were significant differences in flow experiences between the two groups. Semi structured interviews served as the primary source for qualitative data, which were subsequently coded and categorized to reduce single-method bias and to enhance cross validation. Results showed that solo walkers experienced higher flow across all nine dimensions compared to those walking with companions. However, statistically significant differences emerged specifically in the dimensions of “transformation of time,” “action-awareness merging,” “autotelic experience,” and “feedback.” Qualitative data further highlighted that walking alone allowed individuals to concentrate more fully on the act of walking, enriching their overall experience. The study also found that religious factors influence flow on the Camino, with Catholics having higher flow experiences levels compared to non-Catholics or those without religious affiliations. Additionally, from the perspective of serious leisure theory, long distance hiking on the Camino can indeed be categorized as a form of serious leisure, enhancing both the sense of achievement and the personal growth of participants

Development of high-throughput metabarcoding approaches to explore genetic diversity and anthelmintic resistance in sheep gastrointestinal nematodes

Sheep farming in the UK, integral to its cultural and economic fabric, contends with significant challenges from gastrointestinal nematodes (GINs) which impair livestock productivity and increase mortality, leading to substantial economic losses. The emergence of anthelmintic resistance, compounded by the impacts of climate change, has necessitated integrated parasite management (IPM) strategies and the adoption of advanced DNA technologies such as next-generation sequencing (NGS) for diagnosis and targeted treatment. In this project, rDNA ITS-2 and mt-ND4 genetic markers were employed to analyse GINs across various locations, farms, and treatment groups. The ITS-2 analysis, also known as the Nemabiome, provides robust identification and relative abundance of GIN species when combined with faecal egg count, while mt-ND4 markers offer insights into the origins, gene flow, and infection patterns of individual species. By leveraging these technologies, this thesis aims to enhance the management and understanding of GINs, contributing to the sustainability and productivity of UK sheep farming. A significant portion of the work focused on refining these techniques. Despite the effectiveness of Nemabiome sequencing in detecting all clade V nematodes, identifying lesser-known GIN species remains challenging due to reference sequence gaps, particularly in environments with cross-infections from GINs infecting diverse grazing animals. To address this, the reference library was expanded using various GIN sample sets, listing anticipated GIN species, extracting their ITS-2 rDNA sequences from NCBI GenBank, and enhancing the library through iterative BLAST searches and phylogenetic analyses. Concurrently, mt-ND-4 markers were developed for T. circumcincta and H. contortus, the two most prevalent GIN species in the UK. These mitochondrial markers, typically species-specific, were adapted into a primer multiplex to process both species simultaneously, significantly increasing efficiency and reducing costs. Reference libraries were developed for both species, along with the post-sequencing analysis pipelines, and the multiplex was tested on various laboratory strains, verifying its accuracy and reliability. To implement both these techniques in the field, a DNA biobank was established, collecting over 250 field samples from across Scotland and England to enable comprehensive comparisons across various locations, treatments, and farms. This biobank was further enhanced by the inclusion of nine characterised laboratory strains of H. contortus and seven of T. circumcincta to assist in the comparison of resistance mechanisms and genetic diversity. Nemabiome analysis identified seven GIN species within the UK, with T. circumcincta being the most prevalent, followed by H. contortus and Trichostrongylus vitrinus. Together, these three species accounted for approximately 88% of infections. Significant spatial differences in GIN distribution were observed between areas, with T. circumcincta being prevalent in Scotland and H. contortus in England, likely influenced by climatic conditions. Despite its generally lower presence, H. contortus was consistently found on some Scottish farms, suggesting an influence of local environmental or management factors. It also showed a higher prevalence and diversity in alpacas compared to sheep or other hosts, raising questions about the role of alpacas as a maintenance host. The effectiveness of levamisole, ivermectin, and their combined anthelmintic treatments was assessed through faecal egg count reduction tests (FECRT) across 18 farms in England. Treatments were more effective against some species than others: Resistance was indicated in T. circumcincta, while Trichostrongylus axei and Trichostrongylus colubriformis displayed mixed results. Notably, the combination treatment proved less effective than individual drugs on some farms, which could suggest antagonistic interactions between these drugs. In the mt-ND4 analysis, 60 H. contortus and 35 T. circumcincta amplicon sequence variants (ASVs) were identified, with a single ASV representing over one-third and over 62% of the total reads, respectively. Phylogenetic analysis suggested a common origin for H. contortus, but potentially two distinct origins for T. circumcincta. H. contortus showed a general trend towards balancing selection or population contraction across both areas, while T. circumcincta showed population expansion or purifying selection in Scotland and balancing selection or contraction in England. There was significant gene flow with minimal genetic differentiation between Scottish and English populations across both species. Post-treatment analysis revealed a reduction in genetic diversity for H. contortus but the opposite for T. circumcincta. Ivermectin-treated groups displayed higher H. contortus diversity compared to those treated with levamisole, with the combination yielding moderate diversity levels, supporting the idea of possible antagonistic interactions. No difference was observed between treatment groups for T. circumcincta. Overall, the study underscores regional and inter-species variations, alongside the challenges of emerging anthelmintic resistance, especially in T. circumcincta. It highlights the critical need for continuous monitoring and targeted management strategies to effectively control GIN prevalence and manage resistance within UK sheep farming. Additionally, the findings lay a foundation for utilising more diverse and specific genetic markers to further investigate genetic diversity and resistance mechanisms