Genetic Diversity in Casein Gene Cluster in a Dromedary Camel (C. dromedarius) Population from the United Arab Emirates

Variations in Casein Genes Are Associated with Milk Protein and Fat Contents in Sarda Goats (Capra hircus), with an Important Role of CSN1S2 for Milk Yield

This work aimed to assess the variability of casein genes in a population of 153 bucks and 825 lactating does of the Sarda breed, and to perform association analysis between polymorphic sites and milk yield and composition traits. To genotype the casein genes, we chose an SNP panel including 44 SNPs mapping to the four casein genes CSN1S1, CSN2, CSN1S2, and CSN3. Genotyping (made by KASP™ genotyping assay, based on competitive allele-specific PCR) revealed the high variability of the Sarda goat, and haplotype analysis revealed linkage disequilibrium (LD) between CSN1S1 and CSN2 genes, in addition to two LD blocks within the CSN1S2 and two LD blocks within the CSN3 gene, in bucks and does. Association analysis revealed that variability at all four casein genes was associated with milk protein content, total solids, and milk energy. The three Ca-sensitive casein genes were associated with lipid content, and CSN1S2 showed a unique pattern, with intron variants associated with milk yield, in addition to milk pH, NaCl, and SCS (Somatic Cell Score). This information might prove useful in selection schemes and in future investigations aiming to better understand the biology of lactation, and the direct link between genotype and phenotype.

Bifenthrin induces cell death in bovine mammary epithelial cells via ROS generation, calcium ion homeostasis disruption, and MAPK signaling cascade alteration

Bifenthrin is one of the widely used synthetic pyrethroid insecticides, employed for various purposes worldwide. As lipophilic pyrethroids can easily bind to soil particles, which is why their residues are detected in various environments. Consequently, the toxicity of bifenthrin to non-target organisms can be regarded as an environmental concern. The toxic effects of bifenthrin have been studied in various animal models and cell lines; however, its toxic effects on cattle remain unclear. In particular, gaining insights into the toxic effects of bifenthrin on the mammary lactation system is crucial for the dairy industry. Therefore, we proceeded to investigate the toxic effects of bifenthrin on the bovine mammary epithelial cells (MAC-T cells). We established that bifenthrin inhibited cell proliferation and triggered apoptosis in MAC-T cells. Additionally, bifenthrin induced mitochondrial dysfunction and altered inflammatory gene expression by disrupting mitochondrial membrane potential (MMP) and generating excessive reactive oxygen species (ROS). We also demonstrated that bifenthrin disrupted both cytosolic and mitochondrial calcium ion homeostasis. Furthermore, bifenthrin altered mitogen-activated protein kinase (MAPK) signaling cascades and downregulated casein-related genes. Collectively, we confirmed the multiple toxic effects of bifenthrin on MAC-T cells, which could potentially reduce milk yield and quality.

Sequencing and Characterization of αs2-Casein Gene (CSN1S2) in the Old-World Camels Have Proven Genetic Variations Useful for the Understanding of Species Diversification

The CSN1S2 gene encodes αs2-casein, the third most abundant protein in camel milk. Despite its importance in foals, human nutrition, and dairy processing, the CSN1S2 gene in camels has received little attention. This study presents the first complete characterization of the CSN1S2 gene sequence in Old-World camels (Camelus bactrianus and Camelus dromedarius). Additionally, the gene promoter, consisting of 752 bp upstream of exon 1, was analyzed. The entire gene comprises 17 exons, ranging in length from 24 bp (exons 4, 8, 11, and 13) to 280 bp (exon 17). Interesting was the identification of the exon 12 in both species. The promoter analysis revealed 24 putative binding sites in the Bactrian camel and 22 in dromedary camel. Most of these sites were typical elements associated with milk protein, such as C/EBP-α, C/EBP-β, Oct-1, and AP1. The SNP discovery showed relatively high genetic diversity compared to other camel casein genes (CSN1S1, CSN2, and CSN3), with a total of 34 polymorphic sites across the two species. Particularly noteworthy is the transition g.311G>A in the CSN1S2 promoter, creating a new putative consensus binding site for a C/EBP-β in the Bactrian camel. At the exon level, two novel variants were found. One was detected in exon 6 of the Bactrian camel (g.3639C>G), resulting in an amino acid replacement, p.36Ile>Met. The second variant was found in noncoding exon 17 of dromedary CSN1S2 (g.1511G>T). Although this mutation occurs in the 3'-UnTranslated Region, it represents the first example of exonic polymorphism in the CSN1S2 for this species. This SNP also affects the binding sites of different microRNAs, including the seed sequence of the miRNA 4662a-3p, highlighting its role as a regulatory factor for CSN1S2 gene. A PCR-RFLP was set up for genotyping a dromedary Tunisian population (n = 157), and the minor allele frequency was found to be 0.27 for the G allele, indicating a potential yield improvement margin. The interspersed elements (INEs) analysis revealed 10 INEs covering 7.34% and 8.14% of the CSN1S2 sequence in the Bactrian and dromedary camels, respectively. Furthermore, six elements (A, B, F, H, I, and L) are shared among cattle and camels and are partially found in other ruminants, suggesting a common ancestral origin of these retrotransposons. Conversely, elements C, D, E, and G are specific to camels.

Exploiting morphobiometric and genomic variability of African indigenous camel populations-A review

Camels (Camelus dromedarius) in Africa are adapted to arid and the semi-arid environmental conditions, and are valuable for meat, milk and fiber production. On account of the growing demand for camels in this continent, there is a need for knowledge on their phenotypic and genetic diversity. This is fundamental to sustainable herd management and utilization including the design of appropriate breeding and conservation strategies. We reviewed studies on the phenotypic and genetic characterization, breeding objectives, systems of production, productive and reproductive performances, and pathways for the sustainable rearing and use of camels in Africa. The morphological and genetic diversity, productive and reproductive abilities of African camels suggest the existence of genetic variations that can be utilized for breeds/ecotypes' genetic improvement and conservation. Possible areas of intervention include the establishment of open nucleus and community-based breeding schemes and utilization of modern reproductive technologies for the genetic improvement of milk and meat yields, sustainable management of rangelands, capacity building of the pastoralists and agro-pastoralists, institutional supports, formation of centralized conservation centres and efficient and effective marketing systems.