Search Results (118)

Wool has distinctive biological, physical, and chemical properties that contribute to its value both for the sheep and in global fibre and textile markets. Its fibres are primarily composed of proteins, principally keratin and keratin-associated proteins (KAPs). To better comprehend the genes that underpin key wool traits, this study examined the keratin-associated protein 36-1 gene (KRTAP36-1) in Chinese Tan lambs. We identified three previously reported alleles of the gene (named A, B and C) that were present in the lambs studied, with genotype frequencies as follows: 2.0% (n = 5; AA), 6.9% (n = 17; AB), 13.8% (n = 34; AC), 8.9% (n = 22; BB), 33.4% (n = 82; BC) and 35.0% (n = 86; CC). The frequencies of the individual alleles in the Chinese Tan lambs were 12.4%, 29.1% and 58.5% for alleles A, B and C, respectively. The three alleles were in Hardy–Weinberg Equilibrium. In an association analysis, it was revealed that allele C was associated with variation in the mean fibre curvature of the fine wool of the Chinese Tan lambs, but this association was not observed in their heterotypic hair fibres. This finding suggests that KRTAP36-1 might be differentially expressed in the wool follicles that produce the two fibre types, and that along with other KRTAP genes, it may be involved in determining fibre curvature and the distinctive curly coat of the lambs. Full article

Background: Population persistence for organisms to survive in a world with a rapidly changing climate will require either dispersal to suitable areas, evolutionary adaptation to altered conditions and/or sufficient phenotypic plasticity to withstand it. Given the slow growth and geographically isolated populations of many tree species, there is a high likelihood of local adaption or the acclimation of functional traits in these populations across the UK. Objectives: Given the slow growth and often isolated populations of Tilia cordata (lime tree), we hypothesised that there is a high likelihood of local adaptation or the acclimation of metabolic traits in these populations across the UK. Our aim was to test if the functional metabolomic traits of Tilia cordata (lime tree), collected in situ from natural populations, varied within and between populations and to compare this to neutral allele variation in the population. Methods: We used a metabolic fingerprinting approach to obtain a snapshot of the metabolic status of leaves collected from T. cordata from six populations across the UK. Environmental metadata, longer-term functional traits (specific leaf area) and neutral allelic variation in the population were also measured to assess the plastic capacity and local adaptation of the species. Results: The metabolic fingerprints derived from leaf material collected and fixed in situ from individuals in six populations of T. cordata across its UK range were similar, despite contrasting environmental conditions during sampling. Neutral allele frequencies showed almost no significant group structure, indicating low differentiation between populations. The specific leaf area did vary between sites. Conclusions: The low metabolic variation between UK populations of T. cordata despite contrasting environmental conditions during sampling indicates high levels of phenotypic plasticity. Full article

Background/Objectives: Global warming and rising CO₂ concentrations pose significant challenges to plant systems. Amid these pressures, this study contributes to understanding how tropical species respond by simultaneously evaluating reproductive and genetic traits. It specifically investigates the effects of maternal exposure to warming and elevated CO₂ on progeny physiology, genetic diversity, and population structure in Stylosanthes capitata, a resilient forage legume native to Brazil. Methods: Maternal plants were cultivated under controlled treatments, including ambient conditions (control), elevated CO₂ at 600 ppm (eCO₂), elevated temperature at +2 °C (eTE), and their combined exposure (eTEeCO₂), within a Trop-T-FACE field facility (Temperature Free-Air Controlled Enhancement and Free-Air Carbon Dioxide Enrichment). Seed traits (seeds per inflorescence, hundred-seed mass, abortion, non-viable seeds, coat color, germination at 32, 40, 71 weeks) and abnormal seedling rates were quantified. Genetic diversity metrics included the average (A) and effective (Ae) number of alleles, observed (Ho) and expected (He) heterozygosity, and inbreeding coefficient (Fis). Population structure was assessed using Principal Coordinates Analysis (PCoA), Analysis of Molecular Variance (AMOVA), number of migrants per generation (Nm), and genetic differentiation index (Fst). Two- and three-way Analysis of Variance (ANOVA) were used to evaluate factor effects. Results: Compared to control conditions, warming increased seeds per inflorescence (+46%), reduced abortion (−42.9%), non-viable seeds (−57%), and altered coat color. The germination speed index (GSI +23.5%) and germination rate (Gr +11%) improved with warming; combined treatments decreased germination time (GT −9.6%). Storage preserved germination traits, with warming enhancing performance over time and reducing abnormal seedlings (−54.5%). Conversely, elevated CO₂ shortened GSI in late stages, impairing germination efficiency. Warming reduced Ae (−35%), He (−20%), and raised Fis (maternal 0.50, progeny 0.58), consistent with the species’ mixed mating system; A and Ho were unaffected. Allele frequency shifts suggested selective pressure under eTE. Warming induced slight structure in PCoA, and AMOVA detected 1% (maternal) and 9% (progeny) variation. Fst = 0.06 and Nm = 3.8 imply environmental influence without isolation. Conclusions: Warming significantly shapes seed quality, reproductive success, and genetic diversity in S. capitata. Improved reproduction and germination suggest adaptive advantages, but higher inbreeding and reduced diversity may constrain long-term resilience. The findings underscore the need for genetic monitoring and broader genetic bases in cultivars confronting environmental stressors. Full article

Robinia pseudoacacia is one of the most widely introduced—but also controversial—tree species in Europe. On the one hand, it is valued for its productivity, timber quality, and melliferous blossom. On the other hand, it is highly invasive and causes habitat change and homogenization. The aim of the study reported on here was to assess the genetic diversity of selected R. pseudoacacia stands in Lithuania in districts with the highest black locust stands frequency and to evaluate its spatial distribution in self-establishing stands. To achieve this aim, we employed four nuclear SSR loci (Rops 02, Rops 05, Rops 06, and Rops 08) and investigated the genetic diversity of five R. pseudoacacia plots. The study results reveal that R. pseudoacacia in Lithuania is genetically diverse (the average allele number per plot was 3.66, and the average Ho was 0.83). R. pseudoacacia in the plots forms tight clonal groups that hardly intermix with each other; it also spreads by seeds (66 single-copy genotypes were found in total in all 5 investigated plots). R. pseudoacacia stands in Lithuania originate from different seed sources and from different introduction events, as revealed by the allelic pattern, genetic diversity, and genetic differentiation among the research plots. Full article

Background/Objectives: The Tswana goat, an indigenous Botswana breed, remains genetically understudied despite its adaptation to local conditions. This study characterized its genetic diversity across regions, using Boer goats as a reference, to assess population structure, heterozygosity, and breeding patterns. Methods: Genomic DNA from Tswana goats (Southern, Central, Northwest, and research ranch populations) and Boer goats was genotyped using the Illumina Goat_IGGC_65K_v2 BeadChip. Data were analyzed in PLINK v1.9 and R v4.3.2 to compute genetic diversity indices. Results: Tswana goats showed higher genetic diversity than Boer goats, with greater minor allele frequency (MAF: 0.313 ± 0.127 vs. 0.287 ± 0.136) and expected and observed heterozygosity (Ho: 0.395 ± 0.019 vs. 0.367 ± 0.022, and He: 0.400 vs. 0.375). Regional variation emerged across the Central (Ho = 0.394, He = 0.401, and MAF = 0.320), Southern (Ho = 0.397, He = 0.399, and MAF = 0.318), Northwest (Ho = 0.364, He = 0.358, and MAF = 0.289), and research ranch populations (Ho = 0.394, He = 0.380, and MAF = 0.300). Inbreeding coefficients (F_IS) ranged from mild inbreeding (Central: 0.019) to heterozygote excess (research ranch: −0.038), reflecting managed breeding. Conclusion: Tswana goats have high genetic diversity, with regional variation linked to breeding practices. Although regional structure suggests genetic differentiation, no distinct ecotypes were identified. These findings emphasize the need for controlled breeding to preserve genetic diversity for the Tswana goat. Full article

Background: Non-contact tissue injury in elite athletes is influenced by multiple factors, including genetic predisposition. Although previous research has identified several genetic markers associated with injury susceptibility, the role of the CD36 (cluster of differentiation 36) gene, a key regulator of fatty acid transport into skeletal muscle and other vital tissues, remains unexplored in this context. A single-nucleotide polymorphism in the CD36 gene (rs1761667) involves an A-to-G substitution (with three genotypes = AA and GG homozygotes and AG heterozygotes), and previous data have reported that individuals carrying the AA genotype of the CD36 gene show reduced expression of the CD36 protein and poorer lipid metabolism. Additionally, it has been recently found that the frequency of the AA genotype is significantly lower in elite cyclists compared to field hockey players. No previous study has examined the association between the CD36 rs1761667 polymorphism and athlete injury risk. Therefore, the aim of this study was to investigate the potential association between the CD36 rs1761667 polymorphism and non-contact tissue injury susceptibility in elite Moroccan cyclists and field hockey players. Methods: Forty-three elite Moroccan male athletes, including 19 cyclists and 24 national team field hockey players, volunteered for this study. Non-contact tissue injuries during the 2022/2023 sports season have been recorded. Genotyping of the CD36 rs1761667 polymorphism was carried out using Sanger sequencing. Chi-square tests were used to analyze the Hardy–Weinberg equilibrium and compare the genotypes and characteristics of athletes with and without non-contact injuries. Results: During the 2022/2023 sports season, 21.05% of cyclists (4 out of 19) and 33.33% of field hockey players (8 out of 24) experienced non-contact tissue injuries. The genotypic frequency was similar in the injured and non-injured groups among cyclists (χ² and p not calculated because “AA = 0” in both groups), field hockey players (χ² = 3.30, p = 0.19), and all athletes (χ² = 1.73, p = 0.41). Additionally, the dominant model of the CD36 rs1761667 polymorphism (AA+AG vs. GG) did not reveal a significant risk of non-contact injuries among cyclists (OR: 1.20, 95% CI: 0.13–19.09, p > 0.9999), field hockey players (OR: infinity, 95% CI: 0.23-infinity, p = 0.53), and all athletes (OR: 2.75, 95% CI: 0.32–34.12, p = 0.65). Furthermore, the recessive model (AA vs. AG+GG) did not demonstrate any effect on the risk of non-contact injuries in cyclists (OR and 95% CI not calculated, p > 0.9999), field hockey players (OR: 0.33, 95% CI: 0.05–2.40, p = 0.38), and all athletes (OR: 0.55, 95% CI: 0.10–2.60, p = 0.69). Conclusions: This study suggests that the association between specific genotypes (AA, AG, and GG) or alleles (A and G) of the CD36 gene and susceptibility to non-contact tissue injuries in Moroccan cycling and field hockey players is uncertain. Given the small sample size, further studies will be needed to explore and confirm these findings. Full article

The availability of genome sequences and single-nucleotide polymorphism (SNP) chips allows us to investigate the various genomic characteristics of species by exploring genetic diversity to aid genetic selection. The SNP chip is a cost-effective genotyping platform essential for molecular breeding of livestock. In this study, we developed a liquid SNP capture chip suitable for five Hubei (China) indigenous beef cattle breeds based on whole-genome sequencing datasets. The panel consisted of 42,686 SNPs (~40 K). These SNPs were evenly distributed on each bovine chromosome, with the majority of SNPs having minor allele frequencies >0.05 and located within intergenic regions. The performance evaluation of this SNP chip panel was proceeded by genotyping 200 individuals, revealing that this panel has a high SNP call rate of 99.48%. The SNP chip panel was further used to examine the population structure of a beef cattle population with 205 individuals and demonstrated the ability to differentiate between foreign and indigenous cattle breeds. The SNP chip was also used to determine the runs of homozygosity (ROH) within a local Hubei beef cattle population of 195 individuals. We identified 2547 ROH and several genes associated with economically important traits in the study population. Our findings demonstrate that this chip not only contributes to the understanding of the genetic characteristics of local beef cattle breeds but also provides valuable genetic information for future breeding programs, thereby improving their production efficiency and economic value. Full article

Auricularia heimuer is the second most widely cultivated edible fungus in China, with significant food and medicinal value, and is highly popular throughout Asia and globally. However, the differentiation of A. heimuer is simple, as its morphology is characterized by a small “black disc”, making it difficult to distinguish among germplasms with highly similar agronomic traits, thus posing challenges for germplasm identification. To address this issue, this study conducted whole-genome resequencing analysis on 150 A. heimuer germplasms. Through filtering 9,589,911 SNPs obtained from 280 G resequencing data, a total of 1,202,947 high-quality SNP sites were identified. Based on these high-quality SNPs, population structure analysis, principal component analysis (PCA), and phylogenetic tree analysis revealed that the 150 A. heimuer germplasms could be divided into five groups, with wild strains from the same geographical origin exhibiting significant geographical clustering patterns. This finding underscores the relationship between the genetic diversity of wild A. heimuer and its geographical distribution in China. A further selection of 71 SNP sites was made, and 61 KASP markers were successfully developed using kompetitive allele-specific PCR (KASP) technology, with 54 of them demonstrating good polymorphism. The average values for the polymorphism information content (PIC), minor allele frequency (MAF), gene diversity, and heterozygosity of these core KASP markers were 0.34, 0.35, 0.34, and 0.43, respectively. Based on the 54 core KASP markers, a DNA fingerprinting map of the 150 A. heimuer germplasms was constructed in this study. The findings provide important molecular marker resources and theoretical support for the identification of A. heimuer germplasm, molecular marker-assisted breeding, and the selection of superior varieties. Full article

Background/Objectives: Buffalo populations exhibit distinct genetic variations influenced by domestication history, geographic distribution, and selection pressures. This study investigates the genetic structure and differentiation of 11 buffalo populations, focusing on five loci related to milk protein (CSN1S1 and CSN3) and fat metabolism (LPL, DGAT1 and SCD). The aim is to assess genetic variation between river, swamp, and wild-type buffaloes and identify key loci contributing to population differentiation. Methods: Genetic diversity was analyzed through allele frequency distribution, the Hardy−Weinberg equilibrium testing, and observed (Ho) and expected heterozygosity (He) calculations. Population structure was assessed using principal component analysis (PCA), F_ST statistics, and phylogenetic clustering (k-means and UPGMA tree). The silhouette score (SS) and the Davies−Bouldin index (DBI) were applied to determine optimal population clustering. Results: Significant genetic differentiation was observed between river and swamp buffaloes (p < 0.001). DGAT1 and CSN3 emerged as key markers distinguishing buffalo types. The Italian Mediterranean buffalo exhibited the highest genetic diversity (Ho = 0.464; He = 0.454), while the Indonesian, Chinese, and Vietnamese populations showed low heterozygosity, likely due to selection pressures and geographic isolation. The global F_ST (0.2143; p = 0.001) confirmed moderate differentiation, with closely related populations (e.g., Nepal and Pakistan) exhibiting minimal genetic divergence, while distant populations (e.g., Egypt and Indonesia) showed marked differences, and the Romanian population showed a unique genetic position. Conclusions: These findings contribute to a deeper understanding of buffalo genetic diversity and provide a valuable basis for exploiting the potential of this species in the light of future breeding and conservation strategies specific for each buffalo type. Full article

Background: Walleye (Sander vitreus), a valuable sportfish and an important ecological apex predator, exhibits genetic structuring across their range and localized structuring as a result of stocking. Methods: Walleye from 17 sampling locations across West Virginia were sequenced using a ddRAD protocol, generating various SNP datasets to assess population structuring and genomic diversity, with specific emphasis on the native Eastern Highlands strain. Different minor allele frequency filter thresholds were tested to assess impacts on genetic diversity and differentiation metrics. Results: High genetic differentiation was observed between the Eastern Highlands and Great Lakes strains, with further sub-structuring within the Eastern Highlands strain between the Ohio River populations and the other populations. Increasing MAF thresholds generally reduced the distinctiveness of clusters, but the overall inference of the number of clusters was minimally impacted. Genetic diversity metrics indicated some variability among Eastern Highlands walleye populations, with isolated populations, including the New River and Summersville Lake, showing higher inbreeding coefficients. MAF filters generally increased diversity metrics, but the trend of diversity metrics among populations remained relatively consistent. Several SNPs were found to be potentially undergoing selection, with the minor allele frequencies of these SNPs being found to be highest in Summersville Lake, highlighting potential adaptive divergence between the riverine populations and a large lentic system. Conclusions: The use of any MAF filter generated the same trends of population structuring and genomic diversity inferences regardless of the MAF threshold used. Further management of Eastern Highlands walleye in West Virginia needs to emphasize protecting the genetic integrity of the Kanawha River population and ongoing genomic screening of broodstock to conserve native genetic diversity. Full article

The Danube Clouded Yellow (Colias myrmidone) has experienced one of the most dramatic declines among European butterflies. To estimate genetic diversity in the last population in Poland that has survived in the Knyszyn Forest (KF), we analyzed mitochondrial (COI) and nuclear (EF-1α) polymorphisms in individuals sampled in 2014 and 2022. The results were compared with genetic data obtained in 2014 from a recently extirpated nearby population (Czerwony Bór, CB). Because mtDNA polymorphisms in insects can be modulated by endosymbionts, the samples were screened for Wolbachia. The polymorphism of EF-1α indicated that diversity was gradually decreasing. The KF experienced rapid demographic processes, manifested by a significant change in allele frequency. The small differentiation in nuclear markers between the KF and CB in 2014 suggests that the regional population used to be genetically uniform. Four COI haplotypes that were identified in this study probably belong to two different haplogroups. Wolbachia was detected only in individuals with one specific haplotype, and the prevalence was female-biased, suggesting the induction of two reproductive manipulations. The most common COI haplotype found in Poland was the same as that reported from other parts of Europe, not only for C. myrmidone but also C. caucasica. These results allow us to question the distinctiveness of each taxa. Full article

Min pigs, a prominent local breed from Northeast China, have diverged into two distinct breeds, Ermin (EM) pigs and Hebao (HB) pigs, through prolonged natural and artificial selection. Although these two breeds exhibit distinct differences in body size, the genetic mechanisms underlying this variation remain poorly understood. In this study, we performed whole-genome resequencing and transcriptome analysis on EM and HB pigs to elucidate the genetic basis of body size variation in Min pigs through genome-wide selection signal analysis and the identification of differentially expressed genes (DEGs). The analysis of genetic diversity and population genetic structure across 14 pig breeds revealed that, compared with other breeds, Min pigs present relatively high genetic diversity and a unique genetic structure. Notably, EM pigs exhibited significant genetic differentiation from HB pigs. Integrated analysis of whole-genome resequencing and transcriptome data revealed candidate genes associated with body size variation in Min pigs, including ENPP1, ENPP3, SPP1, CLU, ITGA11, ITGB1, IQGAP2, BMP7, and F2RL2. These genes are enriched primarily in pathways related to ECM–receptor interactions; pantothenate and CoA biosynthesis; starch and sucrose metabolism; nicotinate and nicotinamide metabolism; pyrimidine metabolism; nucleotide metabolism; cellular responses to lipids; biomineral tissue development; biomineralization; and other pathways related to cell signaling, metabolic responses, lipid deposition, and skeletal development. Notably, ITGB1 on chromosome 10 showed strong positive selection in EM pigs, with an SNP locus exhibiting a significant G/A allele frequency difference between EM pigs (G = 52.94%, A = 47.06%) and HB pigs (G = 0%, A = 100%). Our findings suggest that Min pigs potentially modulate lipid metabolism efficiency in adipose tissue through variations in the expression of the ITGB1 gene, potentially contributing to body size differences. These results provide new insights into the genetic mechanisms underlying body size variation in domestic pigs and serve as a valuable reference for identifying and breeding pig breeds with distinct body sizes. Full article

Sophora japonica is an important native tree species in northern China, with high ornamental, medicinal, and ecological value. In order to elucidate the genetic resources of ancient S. japonica, 16 simple sequence repeat (SSR) markers were used to evaluate its genetic diversity and population structure and build a core collection of 416 germplasms from the Shandong, Shanxi, and Hebei provinces. A total of 160 alleles were detected, the mean major allele frequency (MAF)was 0.39, and the mean effective number of alleles (Ne) was 4.08. Shannon’s information index (I), the observed heterozygosity (Ho), the expected heterozygosity (He), and the polymorphism information content (PIC) were 1.58, 0.64, 0.74, and 0.70, respectively, indicating relatively high genetic diversity in ancient S. japonica germplasms. Low genetic differentiation coefficient (Fst = 0.04) and frequent gene flow (Nm = 9.74) were found in the tested S. japonica populations, and an analysis of molecular variance (AMOVA) indicated that the genetic variation mainly came from within individuals (84%). A genetic structure and cluster analysis indicated that 416 ancient S. japonica germplasms could be divided into five subgroups, and there were obvious genetic exchanges among different subgroups. A core collection consisting of 104 (25% of the original collection) germplasms was constructed using the R language package Genetic Subsetter version 0.8 based on the stepwise regression method. The retention rates of the number of alleles (Na), Ne, I, He, and PIC were 87.50%, 106.24%, 103.02%, 102.50%, and 102.74%, respectively. The t-test analysis suggested that there were no significant differences between the core collection and the original collection. The principal coordinate analysis (PCoA) showed that the core collection was uniformly distributed within the initial collection and was able to fully represent the genetic diversity of the original collection. These results provide a scientific basis for the conservation and utilization of ancient S. japonica germplasms. Full article

The cytotoxic T lymphocyte-associated antigen-4 (CTLA4) gene, a member of the immunoglobulin superfamily, is crucial for maintaining immune homeostasis and preventing autoimmune diseases. Studies have shown that polymorphisms in the CTLA4 gene are linked to an increased risk of brucellosis in humans, but its association with brucellosis in goats remains unexplored. In this study, the tissue expression profile of CTLA4 in goats was investigated, and the correlation between InDel polymorphisms in the CTLA4 gene and susceptibility to brucellosis in goats was examined. The findings reveal the widespread expression of CTLA4 in goat tissues, particularly in the spleen and testes. The tested goat populations presented genotypes insertion/insertion (II), insertion/deletion (ID), and deletion/deletion (DD) at both the P1 and P2 loci, and an association analysis revealed significant differences in the distribution of genotypes and allele frequencies at the P1 and P2 loci of the CTLA4 gene between the Brucella goat case and the control groups (p < 0.05). Specifically, compared with the II genotype, the P1 and P2 loci were significantly associated with an elevated risk of brucellosis development in goats under both the codominant (ID/II) and dominant (ID + DD/II) models (P1, p = 0.042, p = 0.016; P2, p = 0.011, p = 0.014). Additionally, haplotype analysis indicated that haplotypes I_P1D_P2, D_P1I_P2, and D_P1D_P2 were significantly associated with an increased risk of brucellosis in goats compared to the reference haplotype I_P1I_P2 (p = 0.029, p = 0.012, p = 0.034). Importantly, the Lipopolysaccharide (LPS) stimulation of peripheral blood monocytes and/or macrophages from goats with the II, ID, and DD genotypes resulted in increased CTLA4 expression levels in the II genotype, leading to a robust LPS-induced inflammatory response. Through bioinformatic analysis, the observed effect of the InDel locus on Brucella pathogenesis risk in goats could be attributed to the differential binding of the transcription factors nuclear factor kappaB (NF-κB) and CCAAT/enhancer-binding protein α (C/EBPα). These findings offer potential insights for breeding strategies against brucellosis. Full article

The αs2-casein is a phosphoprotein secreted in the milk of most mammals, and it is the most hydrophilic of all caseins. Contrary to genes found in ruminants, in donkeys two different encoding genes for donkey αs2-casein (CSN1S2 I and CSN1S2 II) have been identified. However, unlike in ruminants, the variability at these loci has not been characterized in detail in donkeys until now. In this study, we analyze the transcript profile of the donkey CSN1S2 I and CSN1S2 II genes, and we identify and describe the variability of these loci in the Ragusana and Amiatina breeds reared in Italy. The analysis of the CSN1S2 I Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) products and subsequent sequencing showed, in addition to correctly spliced mRNA, seven other minor mRNAs resulting from differential splicing events involving, in various combinations, entire exons (4, 5, 6, and 11), parts of exons (5′ or 3′ end of exon 17), or the recognition of intronic sequences as an exon (exon 12′). Similarly, the transcription analysis of the CSN1S2 II gene revealed a remarkable variability in splicing events, mainly concerning the alternative insertion of an extra exon 7 (named 7′); the first 33 bp of exon 13; or the alternative skipping of exons 9, 10, 11, 12, and 15, and their combinations. At the mRNA level for CSN1S2 I, seven SNPs were observed, five of which led to amino acid changes: p.T73>A, p.I109>V, p.I130>V, p.I146>T, and p.D217>Y. Similarly, nine SNPs were observed at the CSN1S2 II locus, seven of which are non-synonymous: p.L63>F, p.H70>Q, p.D90>N, p.129A>T, p.H131>Y, p.E144>G, and p.F157>S. In addition, the DNA sequencing of exon 17 and flanking introns of the CSN1S2 I gene revealed a G>A transition at the splice acceptor site of CSN1S2 I exon 17 (FM946022.1:c.375-1G>A), resulting in an allele-specific skipping of the first 15 nucleotides of this exon, which encode the peptide 176NKINQ180, and the recognition of an in-frame cryptic splicing acceptor site: arAACAAAATCAACCAG. A genotyping method based on restriction fragment length polymorphism (XbaI PCR-RFLP) was set up for this SNP. In the total population studied (105 Ragusana and 14 Amiatina donkeys), the A allele had a frequency of 0.2437 with no evidence of deviation from the Hardy–Weinberg equilibrium. This study adds new knowledge regarding the genetic variability of αs2-caseins in donkeys and may contribute significantly to the genetic improvement of milk production for this species. Full article