Biology subjects

Ganem, G.

Publications and source records attributed to Ganem, G..

4 recordsLinked to original sources

bioRxiv2025

Aridity shapes adaptive genomic divergence and population connectivity in a Southern African rodent

Elucidating the drivers of evolution in dry environments is central to understanding how organisms respond to climate change. While research on the genomics of adaptation is growing, aridity-driven intraspecific divergence remains poorly quantified. Here, we address this gap by using genomic data from 230 individuals of the arid-adapted four-striped mouse Rhabdomys bechuanae, sampled across an aridity gradient in southern Africa, a region facing increasing aridification. Combining these data with palaeoclimatic reconstructions and present-day aridity indices, we investigate, from a spatio-temporal perspective, how intraspecific genetic variation relates to aridity. Inference of past effective population size revealed a sharp decline in the late Pleistocene, coinciding with regional aridification and potentially reflecting changes in connectivity during dry periods. Current population structure followed a pattern of isolation by distance and mirrored the aridity gradient. Genotype-Environment Association analyses identified SNPs and genes significantly associated with aridity and genetically differentiated among populations, with functions related to water and energy conservation - as expected under arid conditions - as well as neurotransmission. These findings highlight the underappreciated role for neurological processes in coping with water and resource scarcity. More broadly, our integrative genomics approach suggests that aridity shapes population connectivity and adaptation, with implications for climate resilience.

genomics↗

bioRxiv2024

Do sister species respond similarly to dry conditions? An ecophysiological approach in natura

O_LIUnderstanding how organisms respond to seasonal variations in their environment can be a window to their potential adaptability, a classical problem in evolutionary ecology. In the context of climate change, inducing increased aridity and disruption of seasonality, it is crucial to study the extent and limits of species responsiveness. C_LIO_LIHere, the physiological response to food and water shortage during seasonally dry conditions were investigated. We studied populations of two rodent species of the genus Rhabdomys, one arid and one mesic, in a semi-arid zone where their range overlap in South Africa. We measured blood concentrations of markers of kidney and liver function, as well as body condition, at the onset and the end of the dry season. C_LIO_LIWe found similar shifts in blood metabolite levels, in the semi-arid populations of the two species, indicating malnutrition consistent with the observed degradation of habitat quality between the start and the end of the dry season. Furthermore, regardless of the period, differences between the two species in blood metabolite concentrations (e.g. amylase, sodium, alkaline phosphatase) were observed, suggesting contrasting diets and water conservation abilities. C_LIO_LIOverall, we show that, as seasonal dry conditions worsen, organisms are increasingly affected by reduced food availability, and local adaptation to arid conditions may provide the arid species with an advantage to cope with semi-arid conditions. Our study suggests that even mild arid conditions could have a negative impact and questions resilience of animals to harsher arid conditions. C_LI

ecology↗

bioRxiv2022

Divergence of olfactory receptors associated with the evolution of assortative mating and reproductive isolation in mice

AO_SCPLOWBSTRACTC_SCPLOWDeciphering the genetic bases of behavioural traits is essential to understanding how they evolve and contribute to adaptation and biological diversification, but it remains a substantial challenge, especially for behavioural traits with polygenic architectures. In this study, we developed a population genomics approach coupled with functional predictions to address the evolution and genetic basis of olfactory-based assortative mate preferences in the house mouse, suspected to have evolved as a response to selection against hybridisation. We used whole genome resequencing data and the C2 statistic of the program BO_SCPLOWAYC_SCPLOWPO_SCPLOWASSC_SCPLOW, which contrasts allele frequencies corrected for population structure, to characterize genetic differentiation between sets of populations with strong contrast in behaviour (expressing or not assortative mate preferences) and we identified some regions of the genome showing the expected significant and consistent association with behavioural divergence. A series of Olfactory and Vomeronasal Receptor genes, among the most differentiated genomic regions and in line with functional predictions, stand out as the prime candidates underlying this olfactory-based behavioural divergence. These genes form large gene clusters in the genome, with two main candidate clusters extending up to 1.8 Mb. Variant analyses indicate a potential dual role of regulatory and protein-coding changes in the evolution of choosiness. This study shows that combining expectations on the genomic patterns of divergence with functional expectations represents a promising route to unravelling the genetic architecture of complex trait variation and provides novel insights into the role of olfactory and vomeronasal receptors in mammal adaptation and speciation.

evolutionary biology↗

bioRxiv2017

Females prefer cooperative males even when cooperative behavior is unobserved: evidence from the mound-building mouse, Mus spicilegus

Theoretical and empirical studies in humans suggest that cooperative behaviors may act as signals during mate choice. However, cooperation is not always observable by potential partners before mate choice. To address whether cooperative phenotypes are preferred based on cues different from cooperative behaviors per se, we designed an experimental paradigm using wild-born mound-building mice (Mus spicilegus), a species with biparental care. In this species, females cannot observe male cooperative behaviors: mate choice occurs in the spring, whereas mounds are cooperatively built in the fall. We first assessed the variation in mound building investment and identified males exhibiting high and low amounts of cooperation. Second, we presented these males to females during two-way choice tests. As offspring survival relies on mound protection, we hypothesized that mound building could be a form of paternal care and assessed whether cooperative males were more involved in offspring attendance using pup-retrieval experiments. Our results indicate that females were more attracted to highly cooperative males over less cooperative, even when they did not observe them build. This finding suggests that female mate choice is influenced either by cues of cooperativeness different than cooperative behaviors or by preferences for traits associated with cooperativeness. Moreover, male offspring attendance was negatively correlated with cooperativeness, suggesting the potential existence of two alternative paternal strategies in offspring care (mound building versus offspring attendance). Overall, our findings support the existence of preference for cooperative phenotypes in a non-human species and suggest that sexual selection might be involved in the evolution of cooperation.

animal behavior and cognition↗