Biology subjects

Kalthoff, D. C.

Publications and source records attributed to Kalthoff, D. C..

4 recordsLinked to original sources

bioRxiv2026

The population structure and genetic health of European wolves

Once nearly eradicated from Europe, grey wolves (Canis lupus) have recently undergone a remarkable demographic recovery, but their long-term survival remains precarious. By analyzing 1,001 genomes, we uncover a mosaic of distinct evolutionary lineages, not a single recovering population. Northern populations exhibit Asian wolf ancestry, while southern populations preserve ancient Holocene lineages, with dog introgression varying by region. Isolated wolves from the Scandinavian, Italian, and Iberian peninsulas harbored particularly high levels of inbreeding and fixed deleterious mutations. Signatures of genome erosion were widespread across Europe, with many populations falling well short of the minimum size recommended for long-term survival. Our study reveals the complex tapestry of wolf ancestry and variation across Europe, which calls for nuanced, regional conservation plans founded in genetic monitoring.

genomics↗

bioRxiv2025

Ancient balanced polymorphism underlies long-standing adaptation for seasonal camouflage in the least weasel

Unraveling how adaptive traits originate and evolve is key to understanding the mechanisms shaping species diversity and their adaptive potential. Seasonal color molts, from summer-brown to winter-white, evolved in at least 21 mammals and birds to maintain camouflage in environments with seasonal snow, but the occurrence of winter-brown morphs reflects seemingly convergent local adaptation to distinct snow conditions. In the least weasel (Mustela nivalis), alternative winter morphs map to the pigmentation gene MC1R, but the evolutionary history and functional basis of this variation remain unknown. Using in vitro cellular assays, we show that winter-brown coats are caused by a derived protein-coding amino acid substitution that reduces MC1R affinity to its ligands, ASIP and -MSH. Using targeted enrichment and sequencing, we find that this mutation arose de novo within the species, around one million years ago, and was maintained across the geographically structured populations generated during its evolution in Europe. Using simulations, we show that genetic drift cannot explain the long-term maintenance of this variant, which is likely driven by spatially varying selection acting on the phenotypic polymorphism, anchoring local adaptive responses. Our results underscore how long-standing adaptive variation can fuel recurrent adaptation to heterogeneous environments through time.

evolutionary biology↗

bioRxiv2022

When blue turns to grey - Paleogenomic insights into the evolutionary history and extinction of the blue antelope (Hippotragus leucophaeus)

The blue antelope (Hippotragus leucophaeus) is the only large African mammal species to have become extinct in historical times, yet no nuclear genomic information is available for this species. A recent study showed that many alleged blue antelope museum specimens are either roan (H. equinus) or sable (H. niger) antelopes, further reducing the possibilities for obtaining genomic information for this extinct species. While the blue antelope has a rich fossil record from South Africa, climatic conditions in the region are unfavourable to the preservation of ancient DNA. Nevertheless, we recovered two blue antelope draft genomes, one at 3.4x mean coverage from a historical specimen (~200 years old) and one at 2.1x mean coverage from a fossil specimen dating to 9,800-9,300 cal BP, making it currently the oldest palaeogenome from Africa. Phylogenomics show that blue and sable antelope are sister species, confirming previous mitogenomic results, and demonstrate ancient gene flow from roan into blue antelope. We show that blue antelope genomic diversity was much lower than in roan and sable antelopes, indicative of a low population size since at least the early Holocene. This supports observations from the fossil record documenting major decreases in the abundance of blue antelope after the Pleistocene-Holocene transition. Finally, the persistence of this species throughout the Holocene despite low population size suggests that colonial-era human impact was likely a decisive factor in the blue antelopes extinction.

evolutionary biology↗

bioRxiv2020

Wild animal oral microbiomes reflect the history of human antibiotics use

Following the advent of industrial-scale antibiotics production in the 1940s, antimicrobial resistance (AMR) has been on the rise and now poses a major global health threat. Because AMR can be exchanged between humans, livestock and wildlife, evaluating the potential of wild animals to act as AMR reservoirs is essential. We used shotgun metagenomics sequencing of dental calculus, the calcified form of the oral microbial biofilm, to determine the abundance and repertoire of AMR genes in the oral microbiome of Swedish brown bears from museum specimens collected over the last 200 years. Our temporal metagenomics approach allowed us to establish a baseline of natural AMR in the pre-antibiotics era and to quantify a significant increase in total AMR load and diversity of AMR genes that is correlated with human antibiotics use. We also demonstrated that Swedish public health policies were effective in limiting AMR spillover into wildlife.

microbiology↗