The findings suggest that adaptive, cell-mediated immune signaling rather than the innate/macrophage-centred mechanisms emphasized by existing bTB candidate gene panels may be a more productive avenue for future selection studies in Nili-Ravi buffalo, while underscoring the value of buffalo-native coordinate systems for accurate genomic inference in this species.
Abstract
Genomic signatures of selection can reveal loci underlying adaptation and disease resistance in livestock populations, but such analyses in water buffalo (Bubalus bubalis) have historically been constrained by the absence of a chromosome-level, species-native reference genome for SNP array data. We re-analyzed genotype data from 85 Nili-Ravi buffalo (Axiom Buffalo Genotyping 90K array, originally positioned using bovine (Bos taurus, UMD3.1) proxy coordinates, by performing a full coordinate liftover to the buffalo-native UOA_WB_1 assembly using an independently published SNP remapping resource. Following quality control (51,209 markers retained), haplotype phasing, and genome-wide integrated haplotype score (iHS) and Wright’s Fst (case/control) selection scans, we evaluated 14 classical bovine-tuberculosis (bTB) candidate genes and identified six additional genes with putative immune function through an unbiased genome-wide screen. None of the 14 classical candidates (including SLC11A1, the Toll-like receptors, and IFNG) reached genome-wide significance in either scan. In contrast, six novel loci TNFSF18, IL2RB, TNFRSF19, IRF2, IL15, and CD28 showed significant iHS or Fst signals, four of which (TNFSF18, IL2RB, IL15, CD28) converge functionally on T-cell costimulation and cytokine receptor signaling (KEGG pathways map04660 and map04060, Bos taurus proxy annotation). Using extended haplotype homozygosity (EHH) decay, haplotype furcation structure, and per-marker haplotype counts as three independent lines of corroborating evidence, we classified these six genes into confidence tiers: TNFSF18 and IL2RB showed the strongest, most balanced support, while CD28 and IL15 signals were driven by very few haplotypes (3 and 5 of 30, respectively) and should be interpreted cautiously pending replication. These findings suggest that adaptive, cell-mediated immune signaling rather than the innate/macrophage-centred mechanisms emphasized by existing bTB candidate gene panels may be a more productive avenue for future selection studies in Nili-Ravi buffalo, while underscoring the value of buffalo-native coordinate systems for accurate genomic inference in this species.
Drakensberger cattle is indigenous to South Africa and represent a unique genetic resource which is known for its quality beef production and adapted to the harsh climatic conditions. Despite its significance within the beef industry, no high-quality chromosomal level genome has been reported for this breed, limiting genomic selection and conservation efforts. Although there is a bovine genome reference, we need a breed specific reference to identify breed-unique alleles and structural variants that might not be explained by a distant reference. To address this, we generated a haplotype resolved assembly for Drakensberger cattle using a trio-binning where we employed PacBio HiFi reads for sire and dam, a combination of PacBio HiFi reads, Oxford Nanopore Technologies reads and Omni-C reads for the offspring. The assembled diploid genome size is 2.89 Gb with a scaffold N50 of 111 Mb and contig N50 of 61 Mb. The consensus accuracy was exceptionally high (QV = 70.23) and a genome completeness of 97.5%, as analysed by the Benchmarking Universal Single-Copy Orthologs (BUSCO). The k-mer profiling suggested one of the strong haplotype separation for livestock with the paternity assembly containing 97.1% and maternity with 99.0%, combined diploid genome recovered 99.46% of all the statistically solid read k-mers. We identified 14 telomeric ends across 13 scaffolds. The final genome encompassed a total of 22,854 protein-coding genes. This is the first high-quality, haplotype resolved genome assembly of the Drakensberger breed. This assembly high accuracy, contiguity and completeness place the genome among the highest-quality cattle genomes produced to date. This genomic resource is essential in designing programs to studies for breed evolution, adaptation, genomic selection and for conservation of the South African indigenous resources.
N. Mapholi, T. Tshilate, R. Smith et al.· Scientific Data· 0 citations
Background: This study aimed to identify genomic regions under selection in Kangayam cattle of Tamil Nadu using a de-correlated composite of multiple signals (DCMS) framework. Methods: BovineHD SNP array data were retrieved from the WIDDE repository and the ICAR Krishi-Kosh portal. After quality control, autosomal SNPs were used for subsequent analyses. Fixation index, integrated haplotype score, modified haplotype homozygosity, Tajima’s D and nucleotide diversity, were calculated and integrated using the DCMS approach. Genomic windows with false discovery rate (FDR) adjusted q less than 0.001 scores were considered for subsequent analysis. Functional annotation, QTL enrichment, protein–protein interaction (PPI) network analysis and hub gene identification were performed to interpret biological relevance. Result: Genomic regions identified after DCMS analysis, harbored genes related to muscle development, metabolism, immunity, thermotolerance, reproduction and milk composition, including MSTN, BMP7, PRKAG3, BoLA-DRB3, IL8R, ABCA1 and members of the SLCO gene family. PPI and hub gene analyses highlighted transport and metabolic pathways, with SLC22A7 and ABCC9 emerging as key nodes. This study presents the first DCMS-based selection signature map for Kangayam cattle, uncovering coordinated selection across interconnected biological pathways.
Asad Khan, Ishmeet Kumar, J. Vyas et al.· Indian Journal of Animal Res...· 0 citations
This research provides the first extensive breed‑pool whole‑genome sequencing (WGS) analysis across five Egyptian sheep populations: Barki (BAR), Rahmani (RAH), their crossbred offspring (CRS), Ossimi (OSI) and Awassi (AWI). To establish a genomic atlas of the genetic architecture of production and adaptation in Egyptian sheep, providing a baseline for future candidate gene discovery and conservation strategies. Through Illumina sequencing of 120 samples, we compiled a dataset exceeding 470 Gb, with mean coverage depths spanning 24.2x to 41.3x. Variant profiling, functional annotation, KEGG pathway analysis, and independent structural variant analysis were conducted. Phenotypic data were collected and validated through qRT-PCR gene expression analysis. Variant profiling revealed between 11.9 and 17.4 million SNPs per breed after stringent filtering. Heterozygosity patterns (population‑level estimates) differed substantially between groups, recorded at 60.41% in the CRS crossbred versus 74.92–85.01% in the purebred lines. Functional annotation identified conserved enrichment related to xenobiotic detoxification and lipid metabolism. KEGG pathway analysis prioritized the PPAR signalling pathway (map03320) and fatty acid metabolism (map01212) as highly significant (p < 0.0001). Independent structural variant analysis identified distinct genomic hotspots on chromosomes 2, 6 and 18, overlapping candidate genes; FABP4, KAP cluster and MSTN implicated in the regulation of fat deposition and muscle development. Phenotypic data confirmed a high degree of breed divergence (p < 0.001). RAH and CRS individuals reached higher body condition scores (BCS 4.31‑ 4.53) and increased fat deposition, whereas BAR was significantly leaner (BCS 2.53). The highest trimmed meat yields were observed in CRS (23.95 kg) and RAH (18.40 kg) (p < 0.001), with RAH also displaying the highest intramuscular fat content at 4.20%. qRT‑PCR validation showed elevated expression of lipogenic genes (ACACA, FASN and FABP4) in fat‑tailed breeds and differential expression of myogenic regulators (MSTN and IGF‑1) correlating with muscularity variations. The current findings establish a genomic atlas for the genetic architecture of production and adaptation in Egyptian sheep, providing a baseline for future genetic and conservation strategies. Formal selection signature analyses, such as XP‑EHH and iHS are recommended for subsequent studies.
Nada N A M Hassanine, Ali H. Amin, E. Hafez et al.· BMC Biotechnology· 0 citations
A new approach to identify environment-specific quantitative trait loci (QTL) using GWAS and the validated resistance gene Yr27 was identified as sole candidate gene for one QTL region of particular relevance for Central European wheat.
Jiao-Jiao Wang, Renate H. Schmidt, Guoliang Li et al.· Theoretical and Applied Gene...· 0 citations
Structural variants (SVs) are a major yet underused source of adaptive variation in aquaculture. We built a genome‐wide SV atlas for 180 Penaeus vannamei from six commercial breeding populations and discovered 1,159,046 SVs, with uneven chromosomal distributions and multi‐type hotspots. Over 63.53% of SVs overlapped repeats—especially simple sequence repeats, DNA transposons, and LINEs. SV and SNP densities were highly correlated. Across populations, 482 k SVs were shared and 145,623 were singletons; the fraction of deletions increased from shared to singleton classes. BMK and KH harbored more singletons than SIS, RH, and CP, indicating greater divergence. PCA and ADMIXTURE recovered three major clusters and revealed the substructure in RH, mirroring SNP analyses. Selection scans identified 78–193 sweep windows per population encompassing 38–161 candidate genes. These genes were predominantly enriched in population‐specific processes such as chromatin regulation, meiotic recombination, membrane‐associated functions, suggesting that structural variants may contribute to divergence in reproductive, metabolic, and structural pathways across breeding programs. Nevertheless, 10 genes showed parallel signals in over 3 populations; many carry short deletions likely affecting regulatory or coding elements. Together, these results show that genome architecture and domestication jointly shape the shrimp SV landscape; that SVs alone robustly resolve population history; and that a small set of recurrent, deletion‐bearing regulatory genes may underpin convergent improvement. The SV map and candidate loci provide diagnostic markers for germplasm tracing and candidate loci for marker‐assisted or genomic selection in P. vannamei breeding.
Ming-Yang Zhao, Hao Wang, Mingxuan Teng et al.· Evolutionary Applications· 0 citations