Nejvíce citovaný článek - PubMed ID 35748392
Genomic analyses show extremely perilous conservation status of African and Asiatic cheetahs (Acinonyx jubatus)
The anthropogenic impact on wildlife is ever increasing. With shrinking habitats, wild populations are being pushed to co-exist in proximity to humans leading to an increased threat of infectious diseases. Therefore, understanding the immune system of a species is key to assess its resilience in a changing environment. The innate immune system (IIS) is the body's first line of defense against pathogens. High variability in IIS genes, like toll-like receptor (TLR) genes, appears to be associated with resistance to infectious diseases. However, few studies have investigated diversity in TLR genes in vulnerable species for conservation. Large predators are threatened globally including leopards and cheetahs, both listed as 'vulnerable' by IUCN. To examine IIS diversity in these sympatric species, we used next-generation-sequencing to compare selected TLR genes in African leopards and cheetahs. Despite differences, both species show some TLR haplotype similarity. Historic cheetahs from all subspecies exhibit greater genetic diversity than modern Southern African cheetahs. The diversity in investigated TLR genes is lower in modern Southern African cheetahs than in African leopards. Compared to historic cheetah data and other subspecies, a more recent population decline might explain the observed genetic impoverishment of TLR genes in modern Southern African cheetahs. However, this may not yet impact the health of this cheetah subspecies.
- MeSH
- Acinonyx * genetika MeSH
- divoká zvířata genetika MeSH
- ekosystém MeSH
- infekční nemoci * MeSH
- lidé MeSH
- Panthera * genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
UNLABELLED: There are only about 7,100 adolescent and adult cheetahs (Acinonyx jubatus) remaining in the wild. With the majority occurring outside protected areas, their numbers are rapidly declining. Evidence-based conservation measures are essential for the survival of this species. Genetic data is routinely used to inform conservation strategies, e.g., by establishing conservation units (CU). A commonly used marker in conservation genetics is mitochondrial DNA (mtDNA). Here, we investigated the cheetah's phylogeography using a large-scale mtDNA data set to refine subspecies distributions and better assign individuals to CUs. Our dataset mostly consisted of historic samples to cover the cheetah's whole range as the species has been extinct in most of its former distribution. While our genetic data largely agree with geography-based subspecies assignments, several geographic regions show conflicting mtDNA signals. Our analyses support previous findings that evolutionary forces such as incomplete lineage sorting or mitochondrial capture likely confound the mitochondrial phylogeography of this species, especially in East and, to some extent, in Northeast Africa. We caution that subspecies assignments solely based on mtDNA should be treated carefully and argue for an additional standardized nuclear single nucleotide polymorphism (SNP) marker set for subspecies identification and monitoring. However, the detection of the A. j. soemmeringii specific haplogroup by a newly designed Amplification-Refractory Mutation System (ARMS) can already provide support for conservation measures. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10592-022-01483-1.
- Klíčová slova
- Conservation genetics, Haplotype assignment, Phylogeography, Population genetics, Subspecies assignment, Wildlife forensics,
- Publikační typ
- časopisecké články MeSH
The cheetah (Acinonyx jubatus, SCHREBER 1775) is a large felid and is considered the fastest land animal. Historically, it inhabited open grassland across Africa, the Arabian Peninsula, and southwestern Asia; however, only small and fragmented populations remain today. Here, we present a de novo genome assembly of the cheetah based on PacBio continuous long reads and Hi-C proximity ligation data. The final assembly (VMU_Ajub_asm_v1.0) has a total length of 2.38 Gb, of which 99.7% are anchored into the expected 19 chromosome-scale scaffolds. The contig and scaffold N50 values of 96.8 Mb and 144.4 Mb, respectively, a BUSCO completeness of 95.4% and a k-mer completeness of 98.4%, emphasize the high quality of the assembly. Furthermore, annotation of the assembly identified 23,622 genes and a repeat content of 40.4%. This new highly contiguous and chromosome-scale assembly will greatly benefit conservation and evolutionary genomic analyses and will be a valuable resource, e.g., to gain a detailed understanding of the function and diversity of immune response genes in felids.
- Klíčová slova
- Felidae, Hi-C, PacBio, conservation genomics, proximity-ligation,
- MeSH
- Acinonyx * genetika MeSH
- anotace sekvence MeSH
- chromozomy genetika MeSH
- fylogeneze MeSH
- genom MeSH
- genomika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: The mammalian Leukocyte Receptor Complex (LRC) chromosomal region may contain gene families for the killer cell immunoglobulin-like receptor (KIR) and/or leukocyte immunoglobulin-like receptor (LILR) collections as well as various framing genes. This complex region is well described in humans, mice, and some domestic animals. Although single KIR genes are known in some Carnivora, their complements of LILR genes remain largely unknown due to obstacles in the assembly of regions of high homology in short-read based genomes. METHODS: As part of the analysis of felid immunogenomes, this study focuses on the search for LRC genes in reference genomes and the annotation of LILR genes in Felidae. Chromosome-level genomes based on single-molecule long-read sequencing were preferentially sought and compared to representatives of the Carnivora. RESULTS: Seven putatively functional LILR genes were found across the Felidae and in the Californian sea lion, four to five genes in Canidae, and four to nine genes in Mustelidae. They form two lineages, as seen in the Bovidae. The ratio of functional genes for activating LILRs to inhibitory LILRs is slightly in favor of inhibitory genes in the Felidae and the Canidae; the reverse is seen in the Californian sea lion. This ratio is even in all of the Mustelidae except the Eurasian otter, which has a predominance of activating LILRs. Various numbers of LILR pseudogenes were identified. CONCLUSIONS: The structure of the LRC is rather conservative in felids and the other Carnivora studied. The LILR sub-region is conserved within the Felidae and has slight differences in the Canidae, but it has taken various evolutionary paths in the Mustelidae. Overall, the process of pseudogenization of LILR genes seems to be more frequent for activating receptors. Phylogenetic analysis found no direct orthologues across the Carnivora which corroborate the rapid evolution of LILRs seen in mammals.
- Klíčová slova
- KIR, LILR, Leukocyte Receptor Complex, carnivora, felids, long-read sequencing,
- MeSH
- Canidae * MeSH
- Carnivora * genetika MeSH
- Felidae * MeSH
- fylogeneze MeSH
- genomika MeSH
- lachtani * MeSH
- leukocyty MeSH
- lidé MeSH
- Mustelidae * MeSH
- myši MeSH
- receptory imunologické genetika MeSH
- receptory KIR genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- receptory imunologické MeSH
- receptory KIR MeSH
This review summarizes the current knowledge on the major histocompatibility complex (MHC) of the family Felidae. This family comprises an important domestic species, the cat, as well as a variety of free-living felids, including several endangered species. As such, the Felidae have the potential to be an informative model for studying different aspects of the biological functions of MHC genes, such as their role in disease mechanisms and adaptation to different environments, as well as the importance of genetic diversity for conservation issues in free-ranging or captive populations. Despite this potential, the current knowledge on the MHC in the family as a whole is fragmentary and based mostly on studies of the domestic cat and selected species of big cats. The overall structure of the domestic cat MHC is similar to other mammalian MHCs following the general scheme "centromere-MHC class I-MHC class III-MHC class II" with some differences in the gene contents. An unambiguously defined orthologue of the non-classical class I HLA-E gene has not been identified so far and the class II DQ and DP genes are missing or pseudogenized, respectively. A comparison with available genomes of other felids showed a generally high level of structural and sequence conservation of the MHC region. Very little and fragmentary information on in vitro and/or in vivo biological functions of felid MHC genes is available. So far, no association studies have indicated effects of MHC genetic diversity on a particular disease. No information is available on the role of MHC class I molecules in interactions with Natural Killer (NK) cell receptors or on the putative evolutionary interactions (co-evolution) of the underlying genes. A comparison of complex genomic regions encoding NK cell receptors (the Leukocyte Receptor Complex, LRC and the Natural Killer Cell Complex, NKC) in the available felid genomes showed a higher variability in the NKC compared to the LRC and the MHC regions. Studies of the genetic diversity of domestic cat populations and/or specific breeds have focused mainly on DRB genes. Not surprisingly, higher levels of MHC diversity were observed in stray cats compared to pure breeds, as evaluated by DRB sequencing as well as by MHC-linked microsatellite typing. Immunogenetic analysis in wild felids has only been performed on MHC class I and II loci in tigers, Namibian leopards and cheetahs. This information is important as part of current conservation tasks to assess the adaptive potential of endangered wild species at the human-wildlife interface, which will be essential for preserving biodiversity in a functional ecosystem.
- Klíčová slova
- Felis catus, comparative genomics, conservation genetics, domestic cat, felidae, genetic diversity, major histocompatibility complex, natural killer cell receptor ligands,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH