Biology subjects

Koepfli, K.-P.

Publications and source records attributed to Koepfli, K.-P..

15 recordsLinked to original sources

bioRxiv2026

Disruption of a CCR5-like immunoglobulin gene is linked to plague susceptibility in black-footed ferrets

Black-footed ferrets (Mustela nigripes) are among the worlds most endangered mammals and remain highly vulnerable to sylvatic plague caused by Yersinia pestis, yet the genetic basis of this susceptibility has remained unknown. Current conservation strategies rely on vaccination of captive-bred animals and large-scale flea control with insecticides, approaches that are costly, labor-intensive, and difficult to implement across the species natural range. Several closely related mustelid species, including the domestic ferret, are substantially more resistant to plague, providing an opportunity to identify naturally evolved immune mechanisms through comparative immunogenomics. Here we identify a conserved class of immunoglobulin lambda variable genes encoding unusually long antigen-binding loops with CCR5-mimicking sequence features that are widespread among Caniformia species. Because CCR5 has been implicated in host interactions with Yersinia species, we hypothesized that antibodies encoded by these germline genes contribute to plague resistance through receptor-like molecular mimicry. Consistent with this hypothesis, we show that these genes are under strong purifying selection in mustelids, are actively expressed in antibody repertoires, and monoclonal antibodies encoded by them reduced intracellular Y. pestis survival in macrophages. In contrast, all analyzed black-footed ferrets carried a frameshifting deletion resulting in loss of gene expression. These findings identify a naturally disrupted germline antibody gene as a candidate determinant of plague susceptibility in black-footed ferrets, demonstrating that variation in germline immunoglobulin genes can influence susceptibility to a lethal infectious disease. Ultimately, these findings lay the groundwork for genetically informed conservation management and the development of new antibody-based anti-plague strategies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/734856v2_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@19d8ac1org.highwire.dtl.DTLVardef@a37aorg.highwire.dtl.DTLVardef@1ecd1e0org.highwire.dtl.DTLVardef@c6fd67_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2026

Over-representation of sperm-associated deleterious mutations across wild and ex situ cheetah (Acinonyx jubatus) populations

As purifying selection becomes less effective and inbreeding increases, small populations frequently develop an increased load of genome-wide deleterious mutations. Reflecting this pattern, deleterious mutations in genes associated with fertility and immunity have previously been identified in the cheetah (Acinonyx jubatus), which has had a low effective population size for at least the last 10,000 years. However, the distribution of deleterious mutations across cheetah populations is currently unknown. Here, we analysed novel whole genome resequencing data from 30 ex situ and 9 wild cheetahs. We investigated variation in genetic diversity, genomic measures of inbreeding, and the distribution of deleterious mutations across cheetah populations. South Sudanese and Tanzanian cheetahs showed higher inbreeding and realized load, while Namibian cheetahs had a higher proportion of population-specific deleterious mutations. Genes containing high- or moderate-impact deleterious mutations were significantly enriched for sperm-related functions, highlighting putative causative loci associated with poor sperm quality in cheetahs. Similar levels of genetic diversity and inbreeding were observed in ex situ cheetahs compared to their wild counterparts, providing empirical evidence of the efficacy of captive breeding programmes in maintaining genetic variation in ex situ populations.

genomics↗

bioRxiv2025

Novel chromosome-length genome assemblies of three distinct subspecies of pine marten, sable, and yellow-throated marten (genus Martes, family Mustelidae)

The genus Martes consists of medium-sized carnivores within the family Mustelidae that are commonly known as martens, many of which exhibit extensive geographic variation and taxonomic uncertainty. Here, we report chromosome-length genome assemblies for three subspecies, each representing a different marten species: the Tobol sable (M. zibellina zibellina), the Ural pine marten (M. martes uralensis), and the Far East yellow-throated marten (M. flavigula aterrima). Using linked-read sequencing and Hi-C scaffolding, we generated assemblies with total lengths of 2.39-2.45 Gbp, N50 values of 137-145 Mbp, and high BUSCO scores (93.6-96.4%). We identified 19 chromosomal scaffolds for sable and pine marten, and 20 for yellow-throated marten, which agrees with the known karyotypes of these species (2n=38 and 2n=40, respectively). Annotation predicted ~20,000 protein-coding genes per genome, of which >90% were assigned functional names. Repeats encompass 36.9-40.4% of the assemblies, with a prevalence of LINEs and SINEs, and is conservative across the genus. Synteny analysis of our generated and available marten genome assemblies revealed assembly artifacts in previously published assemblies, which we confirmed through investigation of Hi-C contact maps. Among other rearrangements, we verified a sable-specific inversion on chromosome 11 using the published cytogenetic data. Our assemblies broaden the genomic resources available for Martes, extending coverage to geographically distant and taxonomically significant subspecies. Together, they provide a robust framework for assessing intraspecific genetic diversity, identifying signatures of hybridization, and refining the complex taxonomy of the genus. Beyond conservation and evolutionary applications, these references will facilitate comparative genomics across Mustelidae and other carnivorans.

genomics↗

bioRxiv2025

Genomics of sable (Martes zibellina) x pine marten (Martes martes) hybridization

The sable (Martes zibellina) and pine marten (Martes martes) are two Palearctic mustelids with long-recognized hybrids (kidases), whose fertility was controversial for years. Early genetic studies confirmed hybrids beyond F1, but details remained unclear due to low-resolution methods. Both species were hunted for centuries, but anthropogenic pressures during the 20th-century caused severe bottlenecks in the sable followed by hunting bans and large-scale reintroduction programs across much of its range, including the sympatric zone, potentially affecting hybridization. We resequenced 30 individuals from most of the sables range and Eastern part of pine martens. Among samples, we found a broad spectrum of hybrid types with mosaic recombinant chromosomes that confirm hybrid fertility and indicate crossover is not suppressed in kidases. This necessitates re-evaluation of previous research, as we detected notable discrepancies between STR-based ancestry and whole-genome analysis. In pine martens, we revealed mitochondrial DNA introgression from sables, indicating displacement of native pine marten mitochondrial sequences. Pine marten heterozygosity is relatively low ([~]0.5-0.6 hetSNPs/kbp) while sable diversity ([~]1.5-1.8 hetSNPs/kbp) is unexpectedly high for a species with its demographic history, likely reflecting successful reintroduction programs. We dated species divergence at 1.52 (CI: 1.05-2.06) Mya and identified candidate genes associated with ecological, morphological, and dietary differences, as well as hybrid fertility issues. This study is the first to elucidate marten hybridization at the whole-genome level, opening new research directions for understanding hybridization among Holarctic martens, the genetic consequences of reintroduction programs, and comparative adaptomics.

genomics↗

bioRxiv2025

Comparative genomics and phylogenomics of the Mustelinae lineage (Mustelidae, Carnivora)

Mustelinae are among the most diverse and taxonomically complex subfamilies within the Mustelidae, yet their evolutionary history and genetic diversity remain largely unexplored at the whole-genome level. Here, we present the first comprehensive comparative and phylogenomic study of this lineage, integrating nuclear and mitochondrial genomes from ten species across the Holarctic and Indomalayan realms. Our dataset includes two novel genome assemblies (Mustela strigidorsa, M. sibirica) and an improved genome for M. nivalis, enabling robust cross-species analyses of genome size, chromosomal evolution, genetic diversity, and demographic history. We uncover striking inter-and intraspecific variation in genome-wide heterozygosity and genome size, with evidence of marked homozygosity in some Asian lineages (M. eversmanii, M. sibirica, M. strigidorsa) and remarkable genetic diversity in widespread species such as M. nivalis and M. erminea. Phylogenomic results support the previously suggested split of M. richardsonii from M. erminea, but we found no evidence for speciation within M. nivalis. Ancestral reconstruction of chromosomal rearrangements revealed key chromosomal fissions that shaped the Mustelinae radiation, including early events predating the divergence of modern Mustela species. The results confirmed the ancestral karyotype of Mustela (2n=44) and the Mustelinae (2n=42). Finally, demographic reconstructions exposed species-specific responses to Quaternary climatic cycles, ranging from long-term resilience in M. nivalis to repeated population bottlenecks in M. putorius and M. sibirica. Collectively, our findings establish a genomic foundation for future evolutionary and conservation genomic research on this emblematic Mustelidae lineage.

evolutionary biology↗

bioRxiv2025

Large-scale identification of microsatellite loci from multiple otter (Mammalia, Carnivora, Lutrinae) species using whole genome sequence data

The development of molecular studies on elusive, rare, and/or poorly known species faces challenges due to the lack of suitable markers. Species-specific microsatellite markers minimize bias, offer better performance, and are cost-effective, aiding the development of population genetic studies. The use of whole-genome sequences allows for the development of species-specific microsatellite markers and their survey in closely related species, enabling the discovery of shared markers that can facilitate comparative studies. Lutrinae includes 14 extant species of otters. Despite their worrisome conservation status, due to inherent characteristics of these species that make their study difficult by traditional methods, many of them lack reliable population genetic data, limiting conservation efforts. In this study, we employed a multi-taxon approach to identify a large number of novel microsatellite loci for 11 of the 14 otter species, assessing whether the identified loci were shared among different taxa. We identified a total of 23,320 microsatellite loci across 11 species, which were reduced to 12,573 after stringent filtering criteria. Primer design was completed successfully for 420 and 259 unique loci, considering two minimum melting temperatures. We validated marker efficiency by testing the 81 loci designed for two Asian species. Of these, 51 loci yielded reliable microsatellite genotypes in both species, with 34 showing allelic variation in at least one of them. These results demonstrate that these markers are applicable in empirical genotyping for both their target and closely related ones.

genomics↗

bioRxiv2025

Comparative analysis of mammalian adaptive immune loci revealed spectacular divergence and common genetic patterns

Adaptive immune responses are mediated by the production of adaptive immune receptors, antibodies and T-cell receptors, that bind antigens, thus causing their neutralization. Unlike other proteins, adaptive immune receptors are not fully encoded in the germline genome and result from a complex of somatic processes collectively called V(D)J recombination affecting germline immunoglobulin (IG) and T-cell receptor (TR) loci consisting of template genes. While various existing studies report extreme diversity of antibodies and T-cell receptors, little is known about the diversity of germline IG and TR loci. To overcome this gap, the first comparative analysis of full-length sequences of IG/TR loci across 44 mammalian species from 13 taxonomic orders was performed. First, germline genes counts were shown to correlate in IGH/IGL and TRA/TRB and anticorrelate in IGK/IGL, possibly indicating co-evolution between corresponding chains. Second, structures of IG/TR loci were analyzed, and it was shown that IG/TR loci formed by long arrays of high multiplicity repeats are more common for species that have experienced population bottlenecks. Finally, haplotypes of IG/TR loci with little or no sequence similarity within a species were found, suggesting that they may have a limited potential for homologous recombination. These results demonstrate that IG/TR loci are rapidly evolving genomic regions whose structural variation is shaped by the population history of the species and open new perspectives for immunogenomics studies.

genomics↗

bioRxiv2024

Parameterizing Pantherinae: de novo mutation rate estimates from Panthera and Neofelis pedigrees

Estimates of de novo mutation rates are essential for phylogenetic and demographic analyses, but their inference has previously been impeded by high error rates in sequence data and uncertainty in the fossil record. Here, we directly estimate de novo germline mutation rates for all extant members of Panthera, as well as the closely related outgroup Neofelis nebulosa, using pedigrees. We use a previously validated pipeline (RatesTools) to calculate mutation rate for each species and subsequently explore the impacts of the novel rates on historic effective population size estimates in each of these charismatic felids of conservation concern. Importantly, we find that the choice of reference genome, the data type and coverage, and the individual all impact estimates of the mutation rate. Despite these stochastic effects, we inferred that base pair mutation rates for all species fell between 0.5 and 1.4e-08 per generation per base pair (mean 0.81e-08 {+/-} 0.35-08 across Pantherinae). Our results provide a cautionary view on inter-species mutation rate comparisons, given the error associated with the reference genome choice and sequencing depth of coverage of the individuals.

evolutionary biology↗

bioRxiv2023

Endangered Przewalski's horse, Equus pzrewalskii, cloned from historically cryopreserved cells

Two endangered Przewalskis horse stallions were cloned from fibroblast cells cultured and cryopreserved in 1980. These stallions are clones of a male that lived from 1975-1998 that pedigree analyses identified as a genetically valuable male for present-day conservation breeding. This is the first time that multiple healthy clones have been produced for an endangered species.

zoology↗

bioRxiv2022

Conservation management strategy impacts inbreeding and genetic load in scimitar-horned oryx

In an age of habitat loss and overexploitation, small populations, both captive and wild, are increasingly facing the effects of isolation and inbreeding. Genetic management has therefore become a vital tool for ensuring population viability. However, little is known about how the type and intensity of intervention shape the genomic landscape of inbreeding and mutation load. We address this using whole genome sequence data of scimitar-horned oryx (Oryx dammah), an iconic antelope that has been subject to contrasting management strategies since it was declared extinct in the wild. We show that unmanaged populations are enriched for long runs of homozygosity (ROH) and have significantly higher inbreeding coefficients than managed populations. Additionally, despite the total number of deleterious alleles being similar across management strategies, the burden of homozygous deleterious genotypes was consistently higher in unmanaged groups. These findings emphasise the risks associated with deleterious mutations through multiple generations of inbreeding. As wildlife management strategies continue to diversify, our study reinforces the importance of maintaining genome-wide variation in vulnerable populations and has direct implications for one of the largest reintroduction attempts in the world. Significance statementConservation genetic management is becoming increasingly important for safeguarding and restoring wildlife populations. Understanding how the intensity of intervention influences genomic components of fitness is therefore essential for supporting species viability. We investigate the impact of contrasting management strategies on the genomic landscape of inbreeding and mutation load in captive populations of scimitar-horned oryx. We reveal how several decades of management have prevented the formation of long runs of homozygosity and masked the expression of deleterious mutations. Our findings highlight the dynamics between inbreeding, mutation load and population size and have direct implications for future management of threatened species.

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↗

bioRxiv2021

Genome assembly of the tayra (Eira barbara, Mustelidae) and comparative genomic analysis reveal adaptive genetic variation in the subfamily Guloninae

Species of the mustelid subfamily Guloninae inhabit diverse habitats on multiple continents, and occupy a variety of ecological niches. They differ in feeding ecologies, reproductive strategies and morphological adaptations. To identify candidate loci associated with adaptations to their respective environments, we generated a de novo assembly of the tayra (Eira barbara), the earliest diverging species in the subfamily, and compared this with the genomes available for the wolverine (Gulo gulo) and the sable (Martes zibellina). Our comparative genomic analyses included searching for signs of positive selection, examining changes in gene family sizes, as well as searching for species-specific structural variants (SVs). Among candidate loci associated with phenotypic traits, we observed many related to diet, body condition and reproduction. For example, for the tayra, which has an atypical gulonine reproductive strategy of aseasonal breeding, we observe species-specific changes in many pregnancy-related genes. For the wolverine, a circumpolar hypercarnivore that must cope with seasonal food scarcity, we observed many changes in genes associated with diet and body condition. All types of genomic variation examined contributed substantially to the identification of candidate loci. This strongly argues for consideration of variation other than single nucleotide polymorphisms in comparative genomics studies aiming to identify loci of adaptive significance.

evolutionary biology↗

bioRxiv2020

Broad Host Range of SARS-CoV-2 Predicted by Comparative and Structural Analysis of ACE2 in Vertebrates

The novel coronavirus SARS-CoV-2 is the cause of Coronavirus Disease-2019 (COVID-19). The main receptor of SARS-CoV-2, angiotensin I converting enzyme 2 (ACE2), is now undergoing extensive scrutiny to understand the routes of transmission and sensitivity in different species. Here, we utilized a unique dataset of 410 vertebrates, including 252 mammals, to study cross-species conservation of ACE2 and its likelihood to function as a SARS-CoV-2 receptor. We designed a five-category ranking score based on the conservation properties of 25 amino acids important for the binding between receptor and virus, classifying all species from very high to very low. Only mammals fell into the medium to very high categories, and only catarrhine primates in the very high category, suggesting that they are at high risk for SARS-CoV-2 infection. We employed a protein structural analysis to qualitatively assess whether amino acid changes at variable residues would be likely to disrupt ACE2/SARS-CoV-2 binding, and found the number of predicted unfavorable changes significantly correlated with the binding score. Extending this analysis to human population data, we found only rare (<0.1%) variants in 10/25 binding sites. In addition, we observed evidence of positive selection in ACE2 in multiple species, including bats. Utilized appropriately, our results may lead to the identification of intermediate host species for SARS-CoV-2, justify the selection of animal models of COVID-19, and assist the conservation of animals both in native habitats and in human care.

genomics↗

bioRxiv2019

Chromosomal-level genome assembly of the scimitar-horned oryx: insights into diversity and demography of a species extinct in the wild

Captive populations provide a valuable insurance against extinctions in the wild. However, they are also vulnerable to the negative impacts of inbreeding, selection and drift. Genetic information is therefore considered a critical aspect of conservation management planning. Recent developments in sequencing technologies have the potential to improve the outcomes of management programmes however, the transfer of these approaches to applied conservation has been slow. The scimitar-horned oryx (Oryx dammah) is a North African antelope that has been extinct in the wild since the early 1980s and is the focus of a long-term reintroduction project. To enable the selection of suitable founder individuals, facilitate post-release monitoring and improve captive breeding management, comprehensive genomic resources are required. Here, we used 10X Chromium sequencing together with Hi-C contact mapping to develop a chromosomal-level genome assembly for the species. The resulting assembly contained 29 chromosomes with a scaffold N50 of 100.4 Mb, and displayed strong chromosomal synteny with the cattle genome. Using resequencing data from six additional individuals, we demonstrated relatively high genetic diversity in the scimitar-horned oryx compared to other mammals, despite it having experienced a strong founding event in captivity. Additionally, the level of diversity across populations varied according to management strategy. Finally, we uncovered a dynamic demographic history that coincided with periods of climate variation during the Pleistocene. Overall, our study provides a clear example of how genomic data can uncover valuable insights into captive populations and contributes important resources to guide future management decisions of an endangered species.

genomics↗

bioRxiv2017

Cryptic phylogeographic history sheds light on the generation of species diversity in sky-island mountains

Biodiversity hotspots should be given high priority for conservation under the situation of global climate change. The sky islands in southwestern China are characterized by extraordinarily high species diversity and are among one of the worlds top biodiversity hotspots. However, neither the actual species diversity in this region or mechanisms generating this diversity are well explored. Here, we report on the phylogeographic analysis of the long-tailed mole (Scaptonyx fusicaudus), a semi-fossorial mammal that inhabits the montane cool forests across the Chinese sky islands and is considered to represent one species divided into two subspecies. Analyses using DNA sequence data from one mitochondrial and six nuclear genes revealed that populations inhabiting different mountains exhibited exceptionally strong geographic structure. The lowlands and large rivers act as \"soft\" and \"hard\" barriers to dispersal, respectively, isolating evolutionary lineages for up to 11 million years. Our results suggest that the mountain ranges act as interglacial refugia buffering populations from climate fluctuations, further facilitating allopatric diversification. Strikingly, species delimitation analyses suggests that the long-tailed mole may comprise 18 operational taxonomic units and 17 putative species. Our results suggest that for low-vagility species, the complex topography of the Chinese sky islands has shaped genetic diversity and structure and promoted exceptional diversification through a combination of eco-environmental stability as well as geographic fragmentation. The patterns observed in S. fusicaudus may be representative for other cold- adapted species, reflecting the generation of mammalian faunal diversity in the sky-island mountains of southwestern China.

zoology↗