Genome-wide landscape of runs of homozygosity and differentiation across Egyptian goat breeds

Detecting the footprint of selection on the genome of Girgentana goat, a popular ancient breed

Girgentana goats are an ancient breed with distinctive morphological, adaptive, and production traits, making this population an interesting model for studying the genetic architecture underlying these traits. These special features result from natural and human-mediated selection. In this study, we aimed to detect potential signatures of selection in the Girgentana genome by combining the following statistical methods: the integrated haplotype score (iHS), the standardised log-ratio of the integrated site-specific extended haplotype homozygosity test between pairs of populations (Rsb), the runs of homozygosity (ROH) islands and the population differentiation index (FST). A composite dataset of 206 Girgentana and 334 animals from 13 goat populations across Northern and Southern Italy was analysed. All animals were genotyped using an Illumina Goat medium-density BeadChip. Multidimensional scaling and neighbour-joining analyses revealed a clear separation of the three major clades, coinciding with Girgentana, Northern, and Southern Italian goats. Twelve regions putatively under selection were detected using iHS and Rsb, whereas 16 hotspot regions were identified using FST and ROH. Notably, a candidate region on chromosome 01 was consistently identified in all four tests. This region, along with other candidate regions, includes several genes associated with adaptive immunity, reproduction, and body size traits. The Girgentana breed showed signals of ongoing selection in a region of chromosome 6 encompassing several milk quality genes, such as caseins (CSN2, CSN1S2, and CSN3). Our study provides a glimpse into the genomic regions harbouring genes that presumably affect the desired features of Girgentana. This highlights the importance of ancient breeds in providing essential genetic traits for adapting livestock to increasing climate change challenges.

Single nucleotide polymorphism-based analysis of linkage disequilibrium and runs of homozygosity patterns of indigenous sheep in the southern Taklamakan desert

Runs of Homozygosity (ROH) are homozygous genomic fragments inherited from parents to offspring. ROH can be used to indicate the level of inbreeding, as well as to identify possible signatures of artificial or natural selection. Indigenous sheep populations on the southern edge of the Taklimakan Desert have evolved unique genetic traits adapted to extreme desert environments. In an attempt to better understand the adaptive mechanisms of these populations under harsh conditions, we used Illumina® Ovine SNP50K BeadChip to perform a genomic characterization of three recognized breeds (Duolang: n = 36, Hetian: n = 84, Qira black: n = 189) and one ecotypic breed (Kunlun: n = 27) in the region. Additionally, we assessed genomic inbreeding coefficients through ROH analysis, revealing insights into the inbreeding history of these populations. Subsequently, we retrieved candidate genes associated with economic traits in sheep from ROH islands in each breed. To better understand the autozygosity and distribution of ROH islands in these indigenous sheep breeds relative to international breeds, we also included three commercial mutton breeds (Poll Dorset: n = 108, Suffolk: n = 163, Texel: n = 150). The study revealed that among seven sheep breeds, Hetian exhibited the shortest linkage disequilibrium (LD) decay distance, while Kunlun demonstrated the highest LD levels. A total of 10,916 ROHs were obtained. The number of ROHs per breed ranged from 34 (Kunlun) to 2,826 (Texel). The length of ROH was mainly 1-5 Mb (63.54%). Furthermore, 991 candidate genes specific to indigenous sheep breeds were identified, including those associated with heat tolerance, adaptability, energy metabolism, reproduction, and immune response. These findings elucidate the genetic adaptation of indigenous sheep in the Taklimakan Desert, uncovering distinctive characteristics of indigenous sheep formation, and advocating for the conservation and genetic enhancement of local sheep populations.

Investigation of selection signatures of dairy goats using whole-genome sequencing data

Dairy goats, a livestock species with a long history of milk production, are essential for the economic advancement of nations, particularly in regions experiencing growth. In this study, we gathered whole-genome resequencing data of 58 goats, including 34 dairy goats and 24 wild goats (Bezoar), to explore the selection signatures linked to milk production traits using ROH (Runs of homozygosity), CLR (composite likelihood ratio), Fst (Fixation index), XP-EHH (Ex-tended haplotype homozygosity across populations) and XP-CLR(Cross-population composite likelihood ratio test) methods. Analysis of five tests of selection signatures for dairy goats revealed a total of 210 genes, with 24 genes consistently identified in at least two approaches. These genes are associated with milk fat, milk protein, and fat yield. Gene enrichment analysis highlighted important GO and KEGG pathways related to milk production, such as the "acyl-CoA metabolic process", "glycerolipid biosynthetic process", "cellular response to fatty ac-id", "hormone metabolic process", "Galactose metabolism". Additionally, genes linked to repro-duction, immune response, and environmental adaptation were identified in dairy goats. The findings from our study offer profound understanding into the critical economic features of dairy goats and offer practical guidance for the improvement and development of crossbreeding initiatives across different dairy goat breeds.

Genome-wide landscape of genetic diversity, runs of homozygosity, and runs of heterozygosity in five Alpine and Mediterranean goat breeds

BACKGROUND

Goat breeds in the Alpine area and Mediterranean basin exhibit a unique genetic heritage shaped by centuries of selection and adaptability to harsh environments. Understanding their adaptive traits can aid breeding programs target enhanced resilience and productivity, especially as we are facing important climate and agriculture challenges. To this aim the genomic architecture of 480 goats belonging to five breeds (i.e., Saanen [SAA], Camosciata delle Alpi [CAM], Murciano-Granadina [MUR], Maltese [MAL], Sarda [SAR]) reared in the Sardinia Island were genotyped and their genomic architecture evaluated to find molecular basis of adaptive traits. Inbreeding, runs of homozygosity (ROH) and runs of heterozygosity (ROHet) were identified. Finally, candidate genes in the ROH and ROHet regions were explored through a pathway analysis to assess their molecular role.

RESULTS

In total, we detected 10,341 ROH in the SAA genome, 11,063 ROH in the CAM genome, 12,250 ROH in the MUR genome, 8,939 ROH in the MAL genome, and 18,441 ROH in the SAR genome. Moreover, we identified 4,087 ROHet for SAA, 3,360 for CAM, 2,927 for MUR, 3,701 for MAL, and 3,576 for SAR, with SAR having the highest heterozygosity coefficient. Interestingly, when computing the inbreeding coefficient using homozygous segment (FROH), SAA showed the lowest value while MAL the highest one, suggesting the need to improve selecting strategies to preserve genetic diversity within the population. Among the most significant candidate genes, we identified several ones linked to different physiological functions, such as milk production (e.g., DGAT1, B4GALT1), immunity (GABARAP, GPS2) and adaptation to environment (e.g., GJA3, GJB2 and GJB6).

CONCLUSIONS

This study highlighted the genetic diversity within and among five goat breeds. The high levels of ROH identified in some breeds might indicate high levels of inbreeding and a lack in genetic variation, which might negatively impact the animal population. Conversely, high levels of ROHet might indicate regions of the genetic diversity, beneficial for breed health and resilience. Therefore, these findings could aid breeding programs in managing inbreeding and preserving genetic diversity.

Whole genome sequencing revealed genetic structure, domestication, and selection of Chinese indigenous ducks

The genetic architecture and domestication history of Chinese indigenous ducks, particularly those with distinct traits like the Longsheng duck (LSD), are not well characterized. This study used whole-genome resequencing data from 540 ducks across 30 populations to explore the genetic diversity and structure of these ducks. Our findings suggest extensive interspecific hybridization between mallard and spot-billed duck. Comparing with other Chinese ducks, LSD is a distinct breed with moderate genetic diversity. Selective signal analysis identified several key genes impacting neural development, fat metabolism, immunity, and circadian rhythms like SLC25A20 and PER2. These genes showed strong selective pressures that parallelled other domestication processes. Additionally, EDNRB2 was identified as a potential gene influencing the unique coloration of LSD's plumage, bill, and webbed feet, associated with distinct mutations in non-coding regions. Comparative analysis with other indigenous breeds further pinpointed genes associated with LSD-specific traits, including plumage color, reproductive capabilities, and fat deposition, such as MITF, SPATA2, EIF2S2, PLIN3, ATP1B1, and CCDC80. Our findings clarify the population genetics of Chinese indigenous ducks. They also highlight key genes and mutations that shape the unique characteristics of LSD. These insights pave the way for further research into the genetic resources and domestication patterns of Chinese ducks.

Genome-wide insights into selection signatures for transcription factor binding sites in cattle ROH regions

Runs of Homozygosity (ROH) regions are characterized by homozygous genotypes inherited from a common ancestor, often arising from positive selection for adaptive traits. These homozygous regions may arise due to inbreeding, selective breeding, or demographic events like population bottlenecks. Transcription factor binding sites (TFBS) are short, specific DNA sequences where transcription factors bind to regulate the expression of nearby genes. These sites are essential for controlling biological processes such as development, metabolism, and immune response. TFBS act as key regulatory elements, and their variations can influence gene activity, contributing to phenotypic differences and adaptation. ROH often encompass regulatory elements, including TFBS, suggesting a functional connection between these genomic features. This study investigates TFBS within ROH regions in 297 animals of six cattle breeds: Gir (48), Tharparkar (72), Vrindavani (72), Frieswal (14), Holstein Friesian (63), and Jersey (28). Utilizing genotyped data of these animals, we identified genomic regions enriched with ROH. We focused on the central 10 kb regions of 50 ROH regions common across all breeds. Within these regions, 450 motifs were examined, identifying 168 transcription factors potentially binding to these regions. The results emphasize the role of TFBS in gene regulation and adaptive processes. By linking ROH patterns to regulatory elements, this study enhances our understanding of the genetic architecture underlying phenotypic traits and their adaptation to environmental pressures. These findings provide insights into the molecular mechanisms influencing genetic variation in cattle populations.

Nucleotide sequence variants, gene expression and serum profile of immune and antioxidant markers associated with brucellosis resistance/susceptibility in Shami goat

Brucellosis is a highly contagious zoonotic bacterial disease. It has considerable negative consequences on the animal production industry worldwide. The objective of this study was to investigate the genetic and molecular variations in Shami goat susceptible to Brucella infection. Blood samples were collected from fifty mature Shami goats (30 Brucella-infected does and 20 non-infection). DNA was extracted and selected parts the immunity; solute carrier family 11 member 1 (SLC11A1), toll-like receptor 1 (TLR1), toll-like receptor 9 (TLR9), SP110 nuclear body protein (SP110), the adenosine A3 receptor (ADORA3), caspase activating recruitment domain 15 (CARD15) and interferon regulatory factor 3 (IRF3), antioxidant glutathione peroxidase 1 (GPX1), nitric oxide synthase (NOS), NAD(P)H dehydrogenase [quinone] 1 (NQO1) and transcription factor NF-E2-related factor 2 (Nrf2) and erythritol related transketolase (TKT), ribose 5-phosphate isomerase (RPIA) and Adenosine monophosphate deaminase (AMPD) genes were sequenced. Likewise, the levels of gene expressions were investigated. The results identified polymorphic variants between healthy and infected does. Levels of gene expression of SLC11A1, TLR1, TLR9, SP110, ADORA3, CARD15, IRF3, HMOX1, TKT, RPIA and AMPD were significantly (P < 0.05) up regulated in the infected compared to the non-infected ones. On the other hand, GPX1, NOS, NQO1 and Nrf2 genes were significantly (P < 0.05) downregulated in the infected compared to the non-infected does. The results of serum profile indicated that there is a significant (P < 0.05) increase in the activities of AST, ALT, GGT, LDH, ALP as well as serum level of globulin, triglycerides, cholesterol, MDA, NO, IL-1β, TNF-α, IgM, IgG, haptoglobin and amyloid A. On the other hand, there were significant reductions in the glucose, total protein albumin, urea, calcium, inorganic phosphorus, sodium, copper, zinc, iron, TAC, GSH, SOD, GPx, IL-10 and fibrinogen in the infected compared to the non-infected does. Our results provide valuable information about the serum profile variations and putative genetic markers for Brucella infection in goats. This could be utilized in controlling goat brucellosis through selective breeding of natural resistant animals.

Examination of homozygosity runs and selection signatures in native goat breeds of Henan, China

Understanding the genomic characteristics of livestock is crucial for improving breeding efficiency and conservation efforts. However, there is a relative lack of information on the genetic makeup of local goat breeds in Henan, China. In this study, we identified runs of homozygosity (ROH), genomic inbreeding coefficients (FROH), and selection signatures in four breeds including Funiu White (FNW), Huai (HG), Lushan Bullleg (LS), and Taihang black (THB). The genomic analysis utilized a dataset of 46,278 SNP markers and 102 animals. A total of 342, 567, 1285, and 180 ROH segments were detected in FNW, HG, LS, and THB, respectively, with an average of 15.55, 29.84, 32.95, and 8.18 segments per individual. The lengths of ROH segments varied from 69.36 Mb in THB to 417.06 Mb in LS, with the most common lengths being 2-4 Mb and 4-8 Mb. The highest number of longest ROH segments (> 16 Mb) were found in LS (328) and the highest average FROH value was observed in LS (0.173), followed by HG (0.128), while the lowest FROH values were in THB (0.029) and FNW (0.070). Furthermore, the analysis of ROH islands and Composite Likelihood Ratio (CLR) identified a total of 175 significant genes. Among these, 25 genes were found to overlap, detected by both methods. These genes were associated with a diverse range of traits including reproductive ability (GPRIN3), weight (CCSER1), immune response (HERC5 and TIGD2), embryo development (NAP1L5), environmental adaptation (KLHL3, TRHDE, and IFNGR1), and milk characteristics (FAM13A). Significant Gene Ontology (GO) terms related to embryo skeletal system morphogenesis, brain ventricle development, and growth were also identified. This study helps reveal the genetic architecture of Henan goat breeds and provides valuable insights for the effective conservation and breeding programs of local goat breeds in Henan.

Genetic structure, selective characterization and specific molecular identity cards of high-yielding Houdan chickens based on genome-wide SNP

The high-yielding Houdan chicken (GGF) is characterized by high egg production and disease resistance. This study conducted whole genome resequencing of the GGF population and compared it to data from other breeds. Genetic diversity analysis revealed higher observed heterozygosity (Ho), Polymorphism information content (PIC), number of runs of homozygosity (ROH), and inbreeding coefficient (FROH) in GGF. Linkage disequilibrium (LD) decay was slowest in GGF, indicating intensive inbreeding and strong selection. These findings suggest a need for appropriate strategies to enhance genetic diversity conservation in this breed. Population structure analysis demonstrated that GGF was genetically distinct from both the red jungle fowl (RJF) and Chinese indigenous chicken (CIC) populations, highlighting GGF as a unique genetic resource warranting intensive protection and utilization. Selective sweep analysis identified genes under selection in GGF, primarily enriched in signaling pathways related to oocyte meiosis and progesterone-mediated oocyte maturation. Key candidate genes included: CCNE1, SKP1, CDC20, CDK2, ADCY8, RPS6KA6, PPP3CB, PDE3B, HSP90AB1, and AKT3. These findings provide a theoretical foundation for their potential application in poultry breeding. Additionally, this study combined bioinformatics analysis with PCR amplification and Sanger sequencing to identify 4 SNPs that can serve as a molecular identity card (ID) for GGF: SNP1 (Chr2: 136130976), SNP3 (Chr4:11705164), SNP4 (Chr4: 63255588), and SNP5 (Chr24: 3271008). This study provides a scientific basis for effective management and conservation of GGF genetic resources, and establishes a simple, economical, and accurate set of molecular IDs to combat the proliferation of inferior breeds and protect genetic resources.

Whole-genome resequencing reveals diversity and selective signals in the Wuxue goat

Animal genetic resources are crucial for ensuring global food security. However, in recent years, a noticeable decline in the genetic diversity of livestock has occurred worldwide. This decline is pronounced in developing countries, where the management of these resources is insufficient. In the current study, we performed whole genome sequencing for 20 Wuxue (WX) and five Guizhou White (GW) goats. Additionally, we utilized the published genomes of 131 samples representing five different goat breeds from various regions in China. We investigated and compared the genetic diversity and selection signatures of WX goats. Whole genome sequencing analysis of the WX and GW populations yielded 120 425 063 SNPs, which resided primarily in intergenic and intron regions. Population genetic structure revealed that WX exhibited genetic resemblance to GW, Chengdu Brown, and Jintang Black and significant differentiation from the other goat breeds. In addition, three methods (nucleotide diversity, linkage disequilibrium decay, and runs of homozygosity) showed moderate genetic diversity in WX goats. We used nucleotide diversity and composite likelihood ratio methods to identify within-breed signatures of positive selection in WX goats. A total of 369 genes were identified using both detection methods, including genes related to reproduction (GRID2, ZNF276, TCF25, and SPIRE2), growth (HMGA2 and GJA3), and immunity (IRF3 and SRSF3). Overall, this study explored the adaptability of WX goats, shedding light on their genetic richness and potential to thrive in challenges posed by climatic changes and diseases. Further investigations are warranted to harness these insights to enhance more efficient and sustainable goat breeding initiatives.

The Transcript Levels and the Serum Profile of Biomarkers Associated with Clinical Endometritis Susceptibility in Buffalo Cows

Determining the gene expression and serum profile of the indicators linked to clinical endometritis susceptibility in Egyptian buffalo cows was the aim of this investigation. The buffalo cows that were enrolled were divided into two groups: forty infected buffalo cows with clinical endometritis and forty seemingly healthy buffalo cows that served as the control group. For the purposes of gene expression and biochemical analysis, ten milliliters of blood was obtained via jugular venipuncture from each buffalo cow. TLR4, IL-8, IL-17, NFKB, SLCA11A1, NCF4, Keap1, HMOX1, OXSR1, ST1P1, and SERP1 were manifestly expressed at much higher levels in the buffaloes with endometritis. On the other hand, the genes that encode SOD, CAT, NDUFS6, Nrf2, and PRDX2 were down-regulated. There was a significant (p < 0.05) elevation of the serum levels of non-esterified fatty acids (NEFAs), beta hydroxy butyric acid (BHBA), triglycerides (TGs), globulin, creatinine, and cortisol, along with a reduction in the serum levels of glucose, cholesterol, total protein albumin, urea, estrogen (E2), progesterone (P4), follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroxine (T4), prostaglandin F2 α (PGF2α), calcium, iron, and selenium, in the endometritis group in comparison with the control. However, no significant change was observed in the values of phosphorus, magnesium, copper, or zinc in either group. Within the selective breeding of naturally resistant animals, the variation in the genes under study and the changes in the serum profiles of the indicators under investigation may serve as a reference guide for reducing endometritis in Egyptian buffalo cows.

Genetic diversity and selection signatures in Hainan black goats revealed by whole-genome sequencing data

Understanding the genetic characteristics of indigenous goat breeds is crucial for their conservation and breeding efforts. Hainan black goats, as a native breed of south China's tropical island province of Hainan, possess distinctive traits such as black hair, a moderate growth rate, good meat quality, and small body size. However, they exhibit exceptional resilience to rough feeding conditions, possess high-quality meat, and show remarkable resistance to stress and heat. In this study, we resequenced the whole genome of Hainan black goats to study the economic traits and genetic basis of these goats, we leveraged whole-genome sequencing data from 33 Hainan black goats to analyze single nucleotide polymorphism (SNP) density, Runs of homozygosity (ROH), Integrated Haplotype Score (iHS), effective population size (Ne), Nucleotide diversity Analysis (Pi) and selection characteristics. Our findings revealed that Hainan black goats harbor a substantial degree of genetic variation, with a total of 23 608 983 SNPs identified. Analysis of ROHs identified 53 710 segments, predominantly composed of short fragments, with inbreeding events mainly occurring in ancient ancestors, the estimates of inbreeding based on ROH in Hainan black goats typically exhibit moderate values ranging from 0.107 to 0.186. This is primarily attributed to significant declines in the effective population size over recent generations. Moreover, we identified 921 candidate genes within the intersection candidate region of ROH and iHS. Several of these genes are associated with crucial traits such as immunity (PTPRC, HYAL1, HYAL2, HYAL3, CENPE and PKN1), heat tolerance (GNG2, MAPK8, CAPN2, SLC1A1 and LEPR), meat quality (ACOX1, SSTR1, CAMK2B, PPP2CA and PGM1), cashmere production (AKT4, CHRM2, OXTR, AKT3, HMCN1 and CDK19), and stress resistance (TLR2, IFI44, ENPP1, STK3 and NFATC1). The presence of these genes may be attributed to the genetic adaptation of Hainan black goats to local climate conditions. The insights gained from this study provide valuable references and a solid foundation for the preservation, breeding, and utilization of Hainan black goats and their valuable genetic resources.

Doppler ultrasonographic scan, gene expression and serum profile of immune, APPs and antioxidant markers in Egyptian buffalo-cows with clinical endometritis

The objective of this study was to elaborate Doppler ultrasonographic scan, genetic resistance and serum profile of markers associated with endometritis susceptibility in Egyptian buffalo-cows. The enrolled animals were designed as; twenty five apparently healthy buffalo-cows considered as a control group and twenty five infected buffalo with endometritis. There were significant (p < 0.05) increased of cervical diameter, endometrium thickness, uterine horn diameter, TAMEAN, TAMAX and blood flow through middle uterine artery with significant decrease of PI and RI values in endometritis buffalo-cows. Gene expression levels were considerably higher in endometritis-affected buffaloes than in resistant ones for the genes A2M, ADAMTS20, KCNT2, MAP3K4, MAPK14, FKBP5, FCAMR, TLR2, IRAK3, CCl2, EPHA4, and iNOS. The RXFP1, NDUFS5, TGF-β, SOD3, CAT, and GPX genes were expressed at substantially lower levels in endometritis-affected buffaloes. The PCR-DNA sequence verdicts of healthy and affected buffaloes revealed differences in the SNPs in the amplified DNA bases related to endometritis for the investigated genes. However, MAP3K4 elicited a monomorphic pattern. There was a significant decrease of red blood cells (RBCs) count, Hb and packed cell volume (PCV) with neutrophilia, lymphocytosis and monocytosis in endometritis group compared with healthy ones. The serum levels of Hp, SAA, Cp, IL-6, IL-10, TNF-α, NO and MDA were significantly (P˂0.05) increased, along with reduction of CAT, GPx, SOD and TAC in buffalo-cows with endometritis compared to healthy ones. The variability of Doppler ultrasonographic scan and studied genes alongside alterations in the serum profile of investigated markers could be a reference guide for limiting buffalo endometritis through selective breeding of natural resistant animals.

Runs of Homozygosity Detection and Selection Signature Analysis for Local Goat Breeds in Yunnan, China

Runs of Homozygosity (ROH) are continuous homozygous DNA segments in diploid genomes, which have been used to estimate the genetic diversity, inbreeding levels, and genes associated with specific traits in livestock. In this study, we analyzed the resequencing data from 10 local goat breeds in Yunnan province of China and five additional goat populations obtained from a public database. The ROH analysis revealed 21,029 ROH segments across the 15 populations, with an average length of 1.27 Mb, a pattern of ROH, and the assessment of the inbreeding coefficient indicating genetic diversity and varying levels of inbreeding. iHS (integrated haplotype score) was used to analyze high-frequency Single-Nucleotide Polymorphisms (SNPs) in ROH regions, specific genes related to economic traits such as coat color and weight variation. These candidate genes include OCA2 (OCA2 melanosomal transmembrane protein) and MLPH (melanophilin) associated with coat color, EPHA6 (EPH receptor A6) involved in litter size, CDKAL1 (CDK5 regulatory subunit associated protein 1 like 1) and POMC (proopiomelanocortin) linked to weight variation and some putative genes associated with high-altitude adaptability and immune. This study uncovers genetic diversity and inbreeding levels within local goat breeds in Yunnan province, China. The identification of specific genes associated with economic traits and adaptability provides actionable insights for utilization and conservation efforts.