Calcagnile, L. | bioRxiv Science

bioRxiv2025

Ecology and demographic structure of an extinct ibex population in Upper Palaeolithic Italian Alps

Alpine Upper Palaeolithic contexts exhibit specialised subsistence strategies, heavily dependent on Capra ibex. Among them, the rock shelter Riparo Dalmeri stands out, with C. Ibex dominating faunal remains across all occupation phases, spanning the Pleistocene/Holocene transition. This evidence positions Riparo Dalmeri as a key site for exploring the interdependence between human groups and C. ibex during one of the most critical climatic and cultural shifts in human evolution. Here, we present the first multidisciplinary study on Late Palaeolithic C. ibex teeth from Riparo Dalmeri, integrating direct radiocarbon dating, isotope (87Sr/86Sr, {delta}13C, {delta}18O), proteomic, and aDNA analyses. We generated the earliest aDNA sequences for C. ibex and contextual evidence on mobility, seasonality, and sex ratios. We found that most C. ibex were local to the area despite consistent human presence. They reveal significant dietary differences between sexes as well as increased seasonality at the Pleistocene-Holocene transition. Our results identify Riparo Dalmeri as an extinct branch of the ibex mtDNA phylogeny, offering unprecedented insights into ibex ecology and evolution that resonate with present-day issues on the conservation of this species in the face of climate change.

ecology↗

bioRxiv2019

Ancient genomes reveal early Andean farmers selected common beans while preserving diversity

All crops are the product of a domestication process that started less than 12,000 years ago from one or more wild populations [1, 2]. Farmers selected desirable phenotypic traits, such as improved energy accumulation, palatability of seeds or reduced natural shattering [3], while leading domesticated populations through several more or less gradual demographic contractions [2, 4]. As a consequence, erosion of wild genetic variation [5] is typical of modern cultivars making them highly susceptible to pathogens, pests and environmental change [6,7]. The loss of genetic diversity hampers further crop improvement programs to increase food production in a changing world, posing serious threats to food security [8,9]. Using both ancient and modern seeds, we analyzed the temporal dynamic of genetic variation and selection during the domestication process of the common bean (Phaseolus vulgaris) that occurred in the Southern Andes. Here we show that most domestic traits were selected for prior to 2,500 years ago, with no or only minor loss of whole-genome variation. In fact, i) all ancient domestic genomes dated between 600 and 2,500 years ago are highly variable - at least as variable as a modern genome from the wild; the genetic erosion that we observe in modern cultivars is therefore a recent process that occurred in the last centuries; ii) the majority of changes at coding genes that differentiate wild and domestic genomes are already present in the ancient genomes analyzed here. Considering that most desirable phenotypic traits are likely controlled by multiple polymorphic genes [10], a likely explanation of this decoupling of selection and genomic erosion is that early farmers applied a relatively weak selection pressure [2] by using many phenotypically similar but genomically diverse individuals as breeders. Selection strategies during the last few centuries were probably less sustainable and produced further improvements focusing on few plants carrying the traits of interest, at the cost of marked genetic erosion.

genomics↗