Search Results (168)

Whole-genome sequencing is a powerful approach for exploring genomic diversity in livestock species. Chickens (Gallus gallus) are an important food source worldwide, and in Taiwan, poultry production contributes substantially to the livestock industry. Taiwan’s commercial red- and black-feathered country chickens dominate this category and play a crucial role in local poultry production. However, fundamental genomic information on their population structure remains limited. To address this gap, this study generated whole-genome sequencing data from red-feathered country chickens originating from four major breeding farms. Genetic diversity analyses revealed uniformly low genetic diversity across all farms. Runs of homozygosity (ROH) analyses indicated predominantly historical inbreeding, with farm-specific differences in recent inbreeding patterns. Population structure analyses revealed clear clustering of individuals according to farm origin, indicating distinct line structures among breeding farms. These results provide the first comprehensive genomic overview of Taiwan’s commercial red-feather country chickens and offer valuable reference information for future breeding strategies and the development of new lines. Full article

Background: idiopathic pulmonary fibrosis (IPF) causes progressive and irreversible changes in the lung parenchyma, leading to respiratory failure. Its pathogenesis involves several damage/repair mechanisms leading to fibrosis, whilst alterations of genes implicated in these processes contribute to the development of the disease. At present, next-generation sequencing (NGS) analyses investigate single-nucleotide or small indel variants, and no evaluation of genomic rearrangements has been so far reported. Methods: In order to identify predisposing variants, we analyzed—both by NGS and by comparative genomic hybridization/single-nucleotide polymorphism (CGH-SNP array) array—37 patients with a diagnosis of familial pulmonary fibrosis. Results: a total of 17 patients (46%) harbored copy number variations (CNVs), 10 (27%) did not harbor any CNVs, 5 (13.5%) showed a mosaic deletion of the Y chromosome, and 5 (13.5%) showed a run of homozygosity (ROH). NGS identified causative variants (including a novel one) in five patients (5/37, 13.5%) and confirmed the high prevalence of MUC5B promoter polymorphism rs35705950, including the detection of a previously unreported form in IPF SNP (indicated as “novel” in the main text), rs141420125 (23/37; 62%). Conclusions: CGH-SNP array identified CNVs containing genes involved in mechanisms (i.e., oxidative stress, mitophagy, NF-Kb pathway) that have been shown to play a role in the pathogenesis of IPF. Therefore, the application of CGH-SNP array or other quantitative tests should be considered in the diagnostic setup of these patients Full article

The Yucatán Black Hairless Pig (YBHP) is an indigenous Mexican breed shaped by tropical environments and traditional management systems. This study aimed to characterize its runs of homozygosity (ROH) and compare its ROH patterns with those of indigenous and commercial pig breeds worldwide using the GGP Porcine 50K SNP array. After applying standard quality-control filters, ROH were identified, classified by length, and evaluated for shared homozygous regions across populations. The YBHP showed intermediate levels of genomic homozygosity (FROH = 0.09), with most ROH segments falling within the 5–20 Mb range. Comparative analyses indicated that the YBHP shared a higher number of ROH segments with indigenous populations than with cosmopolitan breeds. Gene annotation within ROH regions revealed SNPs located in genes previously reported in indigenous populations, including FGF5, BMP2K, PAQR3, RASGEF1B and ANTXR2, which participate in developmental and regulatory biological pathways. Overall, these results provide a detailed description of ROH distribution in the YBHP and offer complementary information to previous studies on its genetic characterization, supporting future conservation and management strategies. Full article

Conservation programmes for two local dairy cattle breeds—Latvian Brown old type (BV) and Latvian Blue (LZ)—commenced in 2004. The aim of this study was to evaluate genetic diversity in the BV and LZ local cattle populations using SNP data. This study was based on genotype data from 96 BV and 75 LZ cows and 20 BV and 18 LZ bulls. The SNPs were determined using the GGP 100K bovine SNP BeadChip. Quality control (QC) and genotype data analysis were performed using PLINK v1.9. The observed heterozygosity was moderate, at around 0.4, for both breeds. Inbreeding coefficients were estimated based on homozygosity runs (F_ROH) to compare recent and ancient inbreeding in the BV and LZ populations. Therefore, the ROH segments were divided into segments with the four classes (1–4 Mb, 4–8 Mb, 8–16 Mb, and above 16 Mb). Shorter ROH regions (ROH < 4 Mb) predominated in the genome. ROH regions with lengths above 16 Mb covers 4–6% of the genome in BV and 11% in LZ population. The average inbreeding coefficient for approximately three generations (F_ROH>16) was 2.30% and 4.87% for BV and LZ cows (p < 0.05), respectively, and 2.59% and 3.85% for BV and LZ bulls, respectively. This study demonstrates that inbreeding has increased from generation to generation (F_ROH>16 is higher compared with F_ROH<16) in both populations. The level of current inbreeding in LZ is higher compared with that in the BV breed. The overall level of inbreeding in the BV and LZ populations is low, but there is a high level of inbreeding among a few animals. The impact of inbreeding on cow productivity has been observed in the LZ and BV cow populations. As a result, breeding organisations need to monitor and control the level of inbreeding and prevent the loss of genetic diversity in these animal populations. Breeders should minimize mating among close relatives; introduce genetically unrelated animals, use pedigree, and genomic information in controlling rates of inbreeding. Full article

MLASA2 is a rare mitochondrial disorder with limited geographic representation in published medical literature. Here, we report the first confirmed case of MLASA2 in a Latin American 16-year-old male harboring a homozygous pathogenic variant p.(Asp311Glu) in the YARS2 gene. The patient presented with sideroblastic anemia and short stature, accompanied by other skeletal dysplasia features not previously associated with MLASA2, including epiphyseal dysplasia, rib edge widening, and poorly defined vertebral structures, but without lactic acidosis. Notably, the patient did not present exercise intolerance but recently exhibited reduced muscle strength. The p.(Asp311Glu) variant, located in the anticodon-binding domain of the mitochondrial tyrosyl-tRNA synthetase (Mt-TyrRS), was consistently predicted to be pathogenic by multiple in silico tools. Molecular modeling revealed that this variant destabilizes the ‘KMSKS’ motif, potentially compromising tRNA recognition fidelity and aminoacylation efficiency. Analysis of runs of homozygosity (ROH) revealed significantly elevated consanguinity (ROH: 31.93%), consistent with a consanguineous mating between biological parents. This case expands the geographic distribution of MLASA2, documents previously unreported phenotypes, suggests a novel pathogenic mechanism, and demonstrates the utility of genomic approaches for diagnosing rare mitochondrial disorders in the absence of complete clinical information and family history. Full article

Fengjing pigs are a Chinese native breed known for their high reproductive ability. Runs of homozygosity (ROHs) have emerged as an effective tool for evaluating inbreeding levels and identifying relevant genes in selection. However, the declining population of Fengjing pigs in recent years has raised concerns about inbreeding. Therefore, this study aimed to investigate the ROH patterns, estimate genomic inbreeding levels, and identify candidate genes associated with economic traits using whole-genome resequencing data from 105 Fengjing pigs. A total of 2448 ROHs were identified, with an average of 23.31 ROHs per individual and an average length of 9.50 Mb. The inbreeding coefficient, based on ROHs, was 0.098. Additionally, three genomic regions with a high frequency of ROHs were identified. These regions contained 64 unique genes, including 14 genes associated with important economic traits. Moreover, six overlapping quantitative trait loci (QTLs) and four candidate genes (HSPG2, CDC42, EPHB2, and GRHL3) were identified on Sus scrofa chromosome (SSC) 6. These QTLs are associated with birth traits (health and reproductive efficiency) and meat development traits (meat quality and growth). This study identified many candidate genes and QTLs that overlapped with ROHs and are associated with economically significant traits. These findings can be used in future breeding, conservation, and utilization of specific Chinese native pig breeds. Full article

Background: The Siberian Husky has evolved as a versatile dog capable of traversing over 1600 km in extreme Arctic conditions, being a competitive show dog in the American Kennel Club, or a favorite pet for companionship. Modern genomics provides an opportunity to explore the biological implications of selection within the Siberian Husky breed for the purpose of sledding, show, or pet. Methods: We identified regions of genetic selection associated with sledding, show, or pet purposes using a whole-genome panel of 234 K SNPs from 237 Siberian Huskies. We assessed allelic variation using Wright’s F_ST and selective sweeps with runs of homozygosity (ROH). Results: Genomic and morphometric measurement principal component analyses identified population structure aligning with breeding purpose. In total, 118 SNPs demonstrated significant allelic variation (F_ST ≥ 0.6) and 22,598 ROH segments were identified within the Siberian Husky breed. ROH islands (n = 91) highlighted selective sweeps, whereas homozygosity association tests characterized regions of the genome under differential selection between populations. Genes within regions were assessed using GO and KEGG pathway analysis for biological insight. Pet dogs showed selection for olfactory performance genes, whereas show dogs were selected for immune function, tissue and nervous system development, and cytoskeletal motor activity. Sledding Siberian Huskies were selected for the development of muscle organs, lung vasculature, limbs, bones, eye structure, and pigmentation, plus genes influencing lipid metabolism and glucose transport. Conclusions: In all, this provides the first evidence of the biological impact of genetic selection within a breed for the distinct sledding, show, and pet purposes while simultaneously maintaining overall population uniformity to meet breed standards. Full article

Background: Longfin batfish (Platax teira) is an important economic species in southern China. In recent years, its wild population has significantly declined due to overfishing. Around 2015, breakthroughs in the artificial large-scale seedling technology for P. teira have promoted the growth of its aquaculture scale in regions such as Hainan and Guangdong. Methods: To study the genetic diversity, inbreeding status, and population structure of the current P. teira farming populations in China, we performed whole-genome resequencing technology and high-density SNP markers to analyze the genetics of four main farming populations. A total of 109 individuals from four populations (NA, ZP, XL, and XC) were sequenced, identifying 5,384,029 high-quality SNPs. Results: The results showed that the nucleotide diversity (π) of each population ranged from 0.00155 to 0.00165 and observed heterozygosity (Ho) ranged from 0.253 to 0.282, which indicated low levels of genetic diversity. The results of the ROH analysis show significant inbreeding in the NA population. Genetic differentiation analysis revealed that the genetic differentiation among NA, XC, and ZP populations was relatively low (F_ST = 0.021–0.029). Conclusions: NA, XC, and ZP populations likely share a common origin of their fry stocks. Based on a phylogenetic tree, principal component analysis (PCA), and population structure analysis, the four populations were divided into four genetic groups. This study is the first analysis of the genetic diversity and population structure of P. teira farming populations in China, laying the foundation for the establishment of a base breeding population and the implementation of genetic improvement programs. Full article

Background: Inbreeding is a major genetic problem that reduces fertility and causes genetic disorders. Some breeders of dromedary camels use the same bull for many years due to its excellent characteristics, leading to mating with offspring and subsequent generations, resulting in increased homozygosity and genetic disorders. We hypothesize that inbreeding is associated with infertility in dromedary camels with normal and uninfected reproductive tracts. Methods: We genotyped 96 samples from seven camel breeds using the Illumina 55K SNP BeadChip, including five confirmed infertile individuals. Inbreeding coefficients (F) were calculated using PLINK based on heterozygosity and runs of homozygosity. Genome-wide association analysis using logistic regression was performed to identify potential genomic regions associated with infertility. Results: All five infertile camels showed significantly higher F values (>0.15) compared to 91 fertile individuals (<0.10, p < 0.001). The genome-wide association analysis failed to identify specific genomic regions linked to infertility, likely due to limited statistical power (n = 5 cases) and the polygenic nature of fertility traits. Population structure analysis revealed genetic differentiation related to coat color, with two significant SNPs on chromosome 3 near SLC30A5 (p < ${10}^{-7}$). Conclusions: Our results demonstrate that elevated inbreeding is strongly associated with infertility in dromedary camels. Future studies should employ larger sample sizes (≥50 infertile individuals) or whole-genome sequencing (35× coverage) to identify specific genomic regions. Implementation of breeding strategies avoiding related matings (F < 0.10) is recommended to maintain reproductive performance in camel herds. Full article

Local livestock genetic resources are crucial for sustainable agriculture and biodiversity conservation. Dengchuan cattle, a nationally protected dairy breed in China, are esteemed for their high milk fat content and cultural significance. However, they have been threatened by crossbreeding with exotic high-yielding breeds, resulting in a decline in purebred resources. In this study, we evaluated the genetic diversity and structure of a conserved population using 100K SNP microarray data from 74 individuals. After implementing strict quality control measures, 78,460 loci were retained for principal component analysis (PCA), which identified 100 SNPs most associated with PC1. After calculating high-consistency loci using PLINK, based on allelic consistency, we selected 61 high-stability markers to represent 60 individuals for further analysis. Genetic diversity parameters indicated moderate polymorphism, with an effective population size (Ne) of 2.293, observed heterozygosity (Ho) of 0.300, expected heterozygosity (He) of 0.326, and an average polymorphic information content (PIC) of 0.261. A paired t-test confirmed a highly significant difference between Ho and He (p < 0.001). Runs of homozygosity (ROH) revealed a moderate level of inbreeding (F_ROH = 0.0928), with bulls exhibiting slightly higher values than females. Neighbor-joining (NJ) clustering further indicated clear lineage distinctions among bulls, but lower kinship among females. Overall, Dengchuan cattle exhibit moderate genetic diversity but face risks due to a small Ne and an unbalanced family structure. Targeted breeding strategies and genetic monitoring are recommended to ensure sustainable conservation and utilization. Full article

Bahaba taipingensis (Chinese bahaba) is a critically endangered fish endemic to China’s coastal waters, valued for both ecological and economic reasons and known as the “panda of the sea”. Captive breeding and stock enhancement are key conservation strategies, yet the genetic composition of released individuals directly affects program outcomes. This study combined mitochondrial and whole-genome resequencing to compare F₁-generation fish with wild populations. At the mitochondrial level, 60 SNPs were detected in F₁ individuals and 72 in wild populations, with haplotype analyses revealing retention of most common maternal lineages but reduced diversity. Nuclear genome analysis showed comparable genetic diversity between groups. Nucleotide diversity (π) was 0.000423 in F₁ fish and 0.000401 in the wild population. However, the F₁ cohort exhibited a higher inbreeding coefficient (F_IS = −0.030) than the wild group (F_IS = −0.118), suggesting early allele frequency shifts, thereby suggesting early genotype frequency shifts. Runs of homozygosity (ROH) analysis showed that the total number and length of ROH regions in the F₁ cohort (686, 283,089.25 kb) were significantly greater than those in the wild population (171, 52,607.30 kb). Genome-wide F_ST between groups was 0.035, and PCA indicated genetic homogenization in F₁ fish. N_e analysis showed that the wild population declined rapidly over generations and stabilized at a low level, indicating genetic diversity loss under environmental stress and highlighting the role of artificial breeding. These findings highlight the need for improved broodstock management and long-term genetic monitoring. Full article

Sheep breeding is an important sector of livestock production in the Republic of Kazakhstan. The Kazakh fat-tailed coarse-wool sheep holds a prominent position among local breeds due to its high meat productivity, resilience to extreme climatic conditions, and efficient use of pasture resources. This study focuses on the analysis of runs of homozygosity (ROH) to evaluate the genetic diversity level, inbreeding and to detect selection signatures in the Kazakh fat-tailed coarse-wool sheep breed. A total of 500 animals were genotyped using the OvineSNP50 BeadChip (Illumina, San Diego, CA, USA). As a result, a total of 41,728 ROH segments were identified, with an average length of 1.59 Mb, distributed across the entire genome. The most prominent homozygous regions were detected on chromosomes OAR10, OAR13, and OAR22, which might be associated with selection signatures. Genomic inbreeding coefficients (F_ROH and F_GRM) showed a strong positive correlation (r = 0.58, p < 0.001), supporting the effectiveness of ROH-based analysis. Several candidate genes were detected, including MYF5, PRDM16, TGM3, SLC26A4 and SMAD5 which are notably involved in muscle formation, wool traits, and fat metabolism. The findings have substantial practical value for breeding programs and for managing genetic diversity in sheep farming enterprises in the Republic of Kazakhstan. Full article

Peruvian Creole goats (PCGs) represent a unique genetic resource shaped by adaptation to diverse environments and traditional breeding practices. In this study, we performed a genomic analysis of six regional populations (Ancash, Ica, Lambayeque, Lima, Piura, and Tumbes) using high-density SNP genotype data. Principal component analysis revealed a moderate genetic structure, with the Ica population showing clear separation and northern populations exhibiting overlap. Runs of homozygosity were predominantly short, and specific regions on chromosome 6 were shared across populations. Inbreeding coefficients were generally low, with Ancash showing the highest values. Linkage disequilibrium decayed rapidly over genetic distance, especially in Piura, indicating higher genetic diversity. Estimates of effective population size revealed decreasing trends across populations, with Piura maintaining the largest recent population size. These findings offer valuable insights into the population structure of Peruvian Creole goats, providing guidance for conservation and sustainable breeding efforts. Full article

The Luhua chicken is an outstanding local breed in China that has been placed under conservation due to the impact of specialized breeding and the widespread adoption of commercial varieties. As such, this study analyzed reproductive traits across three consecutive generations and utilized whole-genome resequencing data from 60 Luhua chickens to assess conservation efficacy through genetic diversity, run of homozygosity (ROH) distribution, kinship, and population structure so as to better conserve the breed. The results show that, across generations, the body weight at first egg increased, the age at first egg was delayed, and the egg weight at first laying increased. No significant variations were found in the body weight at 300 d or the total egg number. The key genetic parameters of the polymorphism information content (PIC), expected heterozygosity (HE), observed heterozygosity (HO), and mean identical-by-state (IBS) distance were 0.234, 0.351, 0.277, and 0.782, respectively. The majority of ROHs ranged from 0.5 to 1 Mb, and the inbreeding coefficient based on ROHs was calculated at 0.021. The findings reveal that these traits remained unchanged across the three generations. Our research suggests that optimizing the mating plan of Luhua chickens is essential to minimize inbreeding risk. Furthermore, the methodology applied in this study provides a valuable reference for the conservation monitoring of other indigenous chicken breeds. Full article

The core objective of racehorse breeding is to enhance the speed and endurance of the horses. The Grassland-Thoroughbred is an emerging horse breed developed in northern China in recent years, characterized by excellent speed performance, enduring stamina, and strong environmental adaptability. However, research on the genetic characteristics within this breed and the genes associated with athletic performance remains relatively limited. We conducted whole-genome resequencing of Grassland-Thoroughbred F1, F2, F3, and the crossbred population (CY) and obtained a total of 4056.23 Gb of high-quality data after quality control. The single nucleotide polymorphisms (SNPs) were primarily distributed in intergenic regions, followed by intronic regions. Principal component analysis (PCA) and STRUCTURE revealed clear distinctions among the generations, with a notable overlap between CY and F3. Using the SNP dataset, we analyzed the number and length distribution patterns of runs of homozygosity (ROHs) in the genomes of different generational groups of Grassland-Thoroughbreds. Short ROHs ranging from 0.5 to 2 Mb were the most abundant, with the following distribution: F1 (85.15%) > F2 (82.92%) > CY (78.75%) > F3 (77.51%). Medium-length ROHs (2–8 Mb) and long ROHs (>8 Mb) together exhibited a similar but opposite trend. The average length of ROHs was 1.57 Mb. The inbreeding coefficients (F_ROH) among different generational groups of Grassland-Thoroughbreds were as follows: F1 (0.0942) < F2 (0.1197) < CY (0.1435) < F3 (0.1497). Through ROH island analysis, 10 high-frequency ROH regions were identified and annotated with 120 genes. Genomic regions and candidate genes associated with athletic traits—ACAD8, OPCML, PRDX2, NTM, NDUFB7, SCL25A15, FOXO1, and SLC4A10—were identified. These genes may play important roles in regulating muscle performance, mitochondrial energy supply, and learning and memory processes in horses and are closely associated with the athletic ability of the Grassland-Thoroughbred population. This study is the first to systematically characterize the genomic diversity and inbreeding dynamics of the Grassland-Thoroughbred during the breeding process. It identifies candidate genes that may influence athletic performance, thereby providing an important molecular foundation and theoretical basis for the genetic improvement and performance-based selection of this emerging breed. Full article