Animal genetics最新文献

Rabbits display a wide range of coat colors, with yellow being a particular phenotype that aids in exploring the molecular mechanisms of coat pigmentation. The Fujian yellow (FJY) rabbit, as China's only indigenous breed with a yellow coat, serves as a valuable genetic resource. Fujian yellow rabbits have predominantly yellow fur, with a diluted white hue on the distal limbs and tail. However, the genetic mechanism underlying yellow coat color remains unclear. To address this, we conducted selection signature analysis to identify candidate genes and potential casual mutations underlying the yellow phenotype in rabbits. Utilizing whole-genome resequencing, a total of 22 486 177 high-quality SNPs were identified from 30 individuals belonging to three Chinese indigenous rabbit breeds featured with yellow or non-yellow phenotype. The results revealed that the ASIP gene on chromosome 4 and the SNAI2 gene on chromosome 3 were under strong selection pressure, both of which play pivotal roles in determining coat color phenotypes. The ASIP gene is involved in melanogenesis across various livestock species, while the SNAI2 gene is linked to hypopigmentation in the distal regions such as the limbs and tail. We further identified two SNP variants, g.23870943C>T in the fourth intron of the ASIP gene, which is closely associated with the yellow phenotype, and g.73725380A>G downstream of the SNAI2 gene, probably contributing to the white shading in Fujian yellow rabbits’ limb and tail regions. These variants are key determinants in the development of the yellow coat color in rabbits. These findings advance the understanding of coat color pigmentation in domestic animals.

A 2-week-old litter of three Old English Sheepdog puppies presented with episodic generalised muscle hypertonia and cyanosis triggered by touch and noise. Owing to poor response to therapy and progression of symptoms, the puppies were euthanised. Post-mortem histology revealed perineuronal incrustations in the spinal cord, suggestive of ischemia or neuronal necrosis. Clinical symptoms, combined with necropsy and histopathology findings, led to a suspicion of startle disease, prompting a referral to a specialised clinical genetics centre. Whole exome sequencing (WES) of the nuclear family identified a homozygous truncating variant in the SLC6A5 gene in affected individuals, with both unaffected parents being heterozygous. Additional population screening found three phenotypically unaffected carriers, indicating that the variant segregates within the Old English Sheepdog breed. This raises concerns about the management of carriers and their breeding contributions if not properly guided by DNA testing. This study addresses a frameshift variant SLC6A5:c.1322del found in Old English Sheepdogs. Next to this, the value of genetic counselling and clinical genetics services in breeding programmes is highlighted to identify carriers and guide informed breeding decisions. Finally, the findings demonstrate the utility of WES in veterinary diagnostics and provide practical insights for breeders, veterinarians and geneticists to improve the health and welfare of Old English Sheepdogs.

For genetic data to be used in forensic casework, it has to be produced within a controlled environment that follows strict quality standards. However, recent reviews have suggested that wildlife forensic laboratories are behind in the development and adherence to appropriate standards for casework. This paper will address these concerns by documenting the standards that have been produced, highlighting the systems of assessment and competency testing available, and reviewing the status of validated reference genetic databases. Networks of dedicated wildlife forensic scientists across the globe, represented in part by the author list for this paper, illustrate the strides taken to build capacity in this field, and an ongoing commitment to present quality wildlife forensic evidence in court.

Stem cells are undifferentiated cells that exhibit a bivalent chromatin state that determines their fate. These cells have potential applications in human and animal health and livestock production. Somatic cell nuclear transfer or cloning is currently being used to produce genetically edited animals. A highly differentiated genome is the main obstacle to correcting epigenetic reprogramming by enucleated oocytes during cloning. Activation of pluripotency genes in the somatic genome is a promising strategy to contribute to more efficient epigenetic reprogramming, improving this technique. Recently, epigenome editing has emerged as a new generation of clustered regularly interspaced short palindromic repeats–clustered regularly interspaced short palindromic repeats-associated protein 9 technology with the aim of modifying the cellular epigenome to turn genes on or off without modifying DNA. Here, we characterize the DNA methylation profile of the CpG island spanning the 5′ untranslated region to intron 1 of the bovine octamer-binding transcription factor (Oct4) gene in gametes, embryos, and fibroblasts. DNA methylation patterns were categorized into three levels: low (0%–20%), moderate (21%–50%), and high (51%–100%). Sperm and embryos showed a hypomethylation pattern, whereas oocytes exhibited a hypo- to moderate methylation pattern. Fetal and adult skin fibroblasts were hypomethylated and moderately methylated, respectively. These results are essential for future studies aimed at manipulating the expression of Oct4. Thus, epigenome editing can be used to turn on the Oct4 in somatic cells to generate induced pluripotent stem cells. This strategy could potentially convert a fully differentiated cell into a cell with certain degree of pluripotency, facilitating nuclear reprogramming by the enucleated oocyte and improving cloning success rates.

Anhidrosis is defined as a decreased or absent ability to sweat in response to heat and exercise. In horses, this condition can increase the risk of life-threatening hyperthermia. A prior study has suggested that equine anhidrosis is associated with a missense variant (rs68643109) in the Potassium Voltage-Gated Channel Subfamily E Regulatory Subunit 4 (KCNE4) gene. This project aimed to validate this association in a population of well-phenotyped horses and to determine the allele frequency of this variant in publicly available whole-genome sequence data. Fifty horses within the University of California Davis Center for Equine Health herd were evaluated for anhidrosis using a series of intradermal terbutaline injections. From existing whole-genome sequence data, the rs68643109 genotype of each horse was identified. When stimulated with terbutaline, all 50 horses produced sweat. All three genotypes at rs68643109 were present in this population of horses; the allele previously associated with anhidrosis (G) was present at a frequency of 0.72. No statistical difference in total sweat score was found (p = 0.31). In whole-genome sequences from 820 other horses reported across three prior studies, the alternative (candidate) allele frequency was similarly high, ranging from 0.52 to 0.68. Since all 50 horses tested in our population produced sweat regardless of genotype, and the previously associated allele is present at a high frequency across datasets, these data fail to validate the missense variant within the KCNE4 gene as causative of or contributing to equine anhidrosis.

The size of the reference population and sufficient phenotypic records are crucial for the accuracy of genomic selection. However, for small-to-medium-sized pig farms or breeds with limited population sizes, conducting genomic breeding programs presents significant challenges. In this study, 2295 Yorkshire pigs were selected from three distinct regions, including 1500 from an American line, 500 from a Canadian line, and 295 from a Danish line. All populations were genotyped using the GeneSeek 50K GGP Porcine HD chip. To enhance genomic selection accuracy, we proposed strategies that combined multiple populations and leveraged multi-omics prior information. Cis-QTL from the PigGTEx database and QTL identified through genome-wide association studies were incorporated into the genomic feature best linear unbiased prediction (GFBLUP) model to predict the ADG100 and the BF100 traits. Results demonstrated that combining multiple populations effectively improved prediction accuracy for small population, accuracy for ADG100 increased by an average of 0.29 and accuracy for BF100 by 0.05. The GFBLUP model, which integrates biological priors, showed some improvements in prediction accuracy for the BF100 trait. Specifically, for the small population, accuracy increased by 0.09 in Scheme 1, where each population size was predicted independently. In Scheme 3, where the large population was used as a reference group to predict the small population, accuracy increased by 0.03. However, the GFBLUP model did not provide additional benefits in predicting the ADG100 trait. These findings offer effective strategies for genetic improvement in developing regions and highlight the potential of multi-omics integration to enhance prediction models.

Domestic dogs exhibit significant diversity in both morphology and personality. Recent studies focusing on large-breed dogs reported the contribution of genetic factors to personality. However, the genetic influence in small-breed dogs remains unexplored. In the present study, we investigated the personality of two small-breed dogs using a questionnaire and genome-wide single-nucleotide polymorphism data obtained from 301 Toy Poodles and 183 Miniature Dachshunds using the Illumina CanineHD 230K SNP BeadChip. The factor analysis conducted on a questionnaire consisting of 39 items identified seven factors. Among the seven personality factors, ‘activeness’ in Toy Poodles and ‘human-directed sociability’ in Miniature Dachshunds had an estimated heritability of 0.425 (SE = 0.311) and 0.514 (SE = 0.355), respectively. In addition, genome-wide association study suggested that two genomic regions possibly affect personality. The dog breeds focused on in this study are most popular in Japan, thus their information is in high demand.

The Bull Terrier (Miniature) and Bull Terrier are two varieties of a dog breed historically divided by size. We identify variety-associated chromosomal regions identified using stratified genome-wide association analysis of 69 Bull Terriers (Miniature) and 33 Bull Terriers. Next, we assess the significance of possible functional variants for body size using height (N = 1458) and weight (N = 1282) of Dog10K individuals with breed-representative metrics available. Variants significant for size across breeds that are consistent with size alleles observed in four Bull Terriers and four Bull Terriers (Miniature) represented in Dog10K are highlighted. From five identified regions, two include genes already known to influence canine body size and a third contains a potential new height gene (ARFGEF3). Near LCORL, the most highly associated variant for height in Bull Terriers was chr3:91734656A>G (p_{Across-breed height} = 2.459 × 10⁻⁹⁹) and for weight it was chr3:91706639G>A (p_{Across-breed weight} = 9.762 × 10⁻⁸⁵). All Bull Terriers (including Miniature) were monomorphic for the derived allele at the known size variant in LCORL (chr3:91872822A>del). In the first exon of IGF2BP2, the derived allele at chr34:18694869-71ins>del significantly reduces both height and weight in Bull Terriers and across breeds (Dog10K breed representative height and weight) (p_{Across-breed height} = 1.65 × 10⁻⁹; p_{Across-breed weight} = 1.79 × 10⁻⁸). The derived allele of the missense variant in ARFGEF3 chr1:30793904G>A, XP_038382065.1 p.V243I significantly reduces breed representative height but not weight (p_{Across-breed height} = 0.01). The effects on the variants assessed are limited to small variants identified in the Dog10K resource using breed-representative sizes.

The 39th International Society for Animal Genetics conference (ISAG) was held for the first time in Africa under the theme ‘Animal genetics for a sustainable future’ in 2023. The conference convened scientists, policy makers, industry professionals, and students from interdisciplinary fields to share and discuss the latest developments in the space of animal genetics. Since its inception as a society, ISAG has sought to provide a platform advocating for a just and equitable future in animal genetics. At the 39th ISAG conference, this commitment towards furthering inclusion in animal genetic science was progressed with two new offerings to attendees. The first session guided discussions on the political, ethical, legal, socioeconomic, and cultural dynamics that present barriers to participating in and benefitting from the genomic and genetic science fraternity. This session also included principles of social justice, specifically equity, diversity, and inclusion, towards enacting fairness in an unfair world, and focused on constraints related to sustainability in animal genetics. The second session used the important tradition of storytelling to transfer knowledge and wisdom from experienced scientists to upcoming researchers. Experienced scientists shared lived experiences on educational and career paths, challenges, and opportunities, providing networking and opportunities for further mentoring. Here, we report on these equity-based actions and their relevance to address the urgent continent-specific and global disparities in animal genetics to move towards a sustainable future.

Body weight is an important trait associated with meat production in the poultry industry. To better understand the genetic basis of body weights in ducks, we estimated genetic parameters and performed a genome-wide association study. The phenotypic values of body weights at ages 0 weeks (bw0) and 8 weeks (bw8) were collected individually from 199 Loumen ducks, and their genotypes were assayed with whole genome re-sequencing. The heritability of bw0 and bw8 are 0.32 and 0.43, respectively, and the genetic correlation of bw0 and bw8 was very low (−7.256e-5). The genome-wide association study results identified eight SNPs significantly associated with bw0 and bw8. The two and nine genes nearest to the significant SNPs were selected as candidate genes: PIK3R5 and MYH10 for bw0, and LOC119717016, RHOJ, PPP2R5E, BRF1, LOC106018961, NUDT14, JAG2, CEP170B, and AKT1 for bw8. Together, the SNPs and candidate genes identified in this study advance understanding of the complex genetic architecture of bw0 and bw8, and provide important clues for future implementation of a genomic selection program in Loumen ducks.