Biology subjects

Hodgson, J. A.

Publications and source records attributed to Hodgson, J. A..

4 recordsLinked to original sources

bioRxiv2026

Fine-scale population structure within and among Malagasy societies

The population of Madagascar exhibits a globally unique combination of African and Asian genetic ancestries. Previous studies have described the admixture history of Madagascar at island-wide scales [1,2], but less focus has been paid to fine-scale population structure across the island. We present new genome-wide genetic data from 192 individuals sampled across five regions of Madagascar. We identify population structure at extremely fine spatial scales ([~]10 km) among the Merina of the central highlands. By analysing subpopulations separately, we found one Merina group exhibited similarity to coastal populations in f4 ratios, estimated admixture dates, and pairwise FST distances, while another group was similar to other highland individuals in the same measures. This fine-scale substructure is likely associated with historical coastal-to-highland migration during the 18th and 19th centuries. In contrast, we also observe macro-scale structure in estimated timing of admixture across the island, with southeastern coastal groups exhibiting the earliest estimated admixture timings, and northern groups exhibiting the latest. This pattern corroborates previous results [1,2], and may suggest differing histories of admixture timing among Malagasy populations. Our results emphasise the importance of deep micro-geographic sampling to complement macro-scale analysis when characterising demographic history.

genetics↗

bioRxiv2025

Hard-to-sample species are more sensitive to land-use change: implications for global biodiversity metrics

Land-use change drives biodiversity loss, but some species suffer more than others. Indicators of global biodiversity change must attempt to summarise these impacts representatively and meaningfully, to guide biodiversity recovery. Yet species that are hard to detect, and thus feature less in relevant databases, might possess traits that make them particularly sensitive to anthropogenic impacts. Using global data for plant, bird, and spider species, we develop a statistical approach to analyse and correct for the impact of excluding hard-to-sample species from global biodiversity indicators. Based on over 4000 species with abundance comparisons available, we found that species with fewer global occurrence records consistently decline more as land-use intensity increases, suggesting that hard-to-sample species are particularly sensitive to land-use differences. When we extrapolate this relationship to all plant, bird and spider species with valid occurrence records (0.27 M species), we obtain a more representative global indicator of overall land-use impacts for these entire taxonomic groups. Our estimates indicate a lower average abundance in anthropogenic land uses compared to results obtained when hard-to-sample species are excluded. For example, intensive agriculture only has 18% of the biodiversity level of primary vegetation, rather than the 47% estimated without extrapolation. We recommend that other existing indicators include an extrapolation solution based on ours, to incorporate the available data as effectively as possible. Using occurrence data to predict species sensitivity unlocks many possibilities to improve global biodiversity indicators, without demanding additional data on poorly known species.

ecology↗

bioRxiv2021

Drosophila larval models of invasive tumourigenesis for in vivo studies on tumour/peripheral host tissue interactions during cancer cachexia.

Cancer cachexia is a common deleterious paraneoplastic syndrome that represents an area of unmet clinical need, partly due to its poorly understood aetiology and complex multifactorial nature. We have interrogated multiple genetically defined larval Drosophila models of tumourigenesis against key features of human cancer cachexia. Our results indicate that cachectic tissue wasting is dependent on the genetic characteristics of the tumour and demonstrate that host malnutrition or tumour burden are not sufficient to drive wasting. We show that JAK/STAT and TNF-/Egr signalling are elevated in cachectic muscle and promote tissue wasting. Furthermore, we introduce a dual driver system that allows independent genetic manipulation of tumour and host skeletal muscle. Overall, we present a novel Drosophila larval paradigm to study tumour/host tissue crosstalk in vivo, which may contribute to future research in cancer cachexia and impact the design of therapeutic approaches for this pathology.

cancer biology↗

bioRxiv2019

Cultural variation in voting patterns reflects the landscape of US genetic diversity: A test of the cultural niche hypothesis.

Humans are unique in the animal world in the extent to which we have the potential to affect our own biological evolution through culturally mediated behavioural variation. However, there is scant clear evidence of the phenomenon. Here, I estimate genetic diversity for every county in the US by merging demographic data from the 2010 US Census with genomic reference populations and show that genetic diversity is predicted by cultural variation as reflected by the 2016 Presidential Election. Remarkably, the 2016 Election alone explains 18% of US county-level variation in genetic diversity, with diversity decreasing as Trump support increases. When state level variation is included in the model, 71% of variation is explained. Within states, genetic segregation increases with cultural segregation. I then tested whether the observed genetic patterns might be explained by culture acting on race and ethnicity and found that genetic diversity tends to increase with racial and ethnic diversity, and that the 2016 Election is an even better predictor of the US landscape of ethnic diversity. Finally, I measured patterns of ethnic assortative mating nationwide from the Census data, and found that ethnic assortment is primarily explained by the proportion of minorities in each county, and that the most diverse counties are the most assortative. Overall, regional variation in cultural tolerance appears to be structuring biological diversity on a massive scale. Also, assortative mating is maintaining ethnic and genetic diversity within the most diverse and tolerant areas. Culture is a primary driver of biological evolution across the US.

evolutionary biology↗