A genomic biomarker for the rapid identification of the rob(1;29) translocation in beef cattle breeds.

Robertsonian translocations, specifically rob(1;29) translocation, have reportedly been the most prevalent chromosomal abnormalities in cattle, affecting various breeds and leading to a decrease in fertility and reproductive value. Currently, the identification of rob(1;29) carriers relies on cytogenetic analysis that has limitations in terms of accessibility, cost, and sample requirements. To address these limitations, a novel genomic biomarker was developed in this study for the rapid and precise identification of rob(1;29) carriers. Using q-PCR, a specific copy number variation associated with translocation was targeted, which effectively distinguished between wild-type, homozygous and heterozygous carriers. Crucially, the biomarker can be applied to DNA extracted from various biological matrices, such as semen, embryos, oocytes, milk, saliva, coat, and muscle, and it is compatible with fresh, refrigerated, or frozen samples. Furthermore, this approach offers significant reductions in cost compared to those associated with traditional cytogenetic analysis and provides results within a short turnaround time. The successful development of this genomic biomarker has considerable potential for widespread adoption in screening programs. It facilitates timely identification and management of rob(1;29) carriers while mitigating economic losses and preserving genetic integrity in bovine populations.

Characterization of Robertsonian and Reciprocal Translocations in Cattle through NGS.

This study presents a novel approach that combines next-generation sequencing (NGS) and cytogenetic technologies for identifying chromosomes involved in chromosomal anomalies. This research focuses on a chromosome anomaly discovered in male Alpine Grey cattle, as well as two previously reported cases of reciprocal translocations (rcps), namely rcp(9;11) and rcp(4;7). Abnormal chromosomes from Alpine Grey cattle were microdissected from conventional preparations, and the amplified products were sequenced using NGS. The sequencing reads were then mapped to the reference genome, and the leverage effect was calculated to identify abnormal reads/Mb values. The result revealed the presence of rob(26;29), which was further confirmed through traditional cytogenetic analyses such as Giemsa staining, CBA-banding, RBA-banding, and FISH techniques. Furthermore, the feasibility of this approach on preserved metaphases was demonstrated through analysis of old slides from previously characterized cases. The study highlights the challenges involved in identifying and characterizing chromosomal aberrations in bovine species and offers a potential solution for analyzing historical anomalies when fresh blood material is unavailable. The combination of NGS and cytogenetic techniques provides a cost-effective and reliable approach for characterizing chromosomal anomalies in various species, including those identified before the availability of modern banding technologies and FISH mapping using specific molecular markers.

Characterization of telomere length in Agerolese cattle breed, correlating blood and milk samples.

Studies into telomere length in cattle are relatively recent and have focused mainly on the Holstein Friesian cattle breed, making it arduous to evaluate the correlation with ageing due to the early age of culling in this breed. Telomere length provides information about the productive lifespan and the quality of farm management, complying with the 'One Health' approach. This study evaluated telomere length in Agerolese cattle, an autochthonous dairy breed characterized by a long productive lifespan (13 years). Multiplex quantitative PCR estimated telomere length in DNA extracted from blood and milk matrices. Interestingly, the results showed longer telomeres in Agerolese (compared to the Holstein Friesian cattle control group), with a negative correlation between telomere length and increasing age and a synchronous trend between blood and milk samples, with a positive correlation between them.

Evaluation of bovine sperm telomere length and association with semen quality.

The study aimed to evaluate if the sperm telomere length can be considered as a new biomarker for sperm quality in bulls. Sperm Telomere Length was evaluated by Monochrome Multiplex Quantitative PCR in group A (n = 8) and group B (n = 8) bulls, classified according to standard semen analysis. Also, this parameter was measured before and after Percoll gradient separation within bulls that produced semen of satisfactory quality. Sperm telomere length, measured as T/S ratio (average ratio of telomere repeats copy number to a single copy gene), was higher in group A than in group B bulls (0.77 ± 0.03 vs 0.43 ± 0.06; P < 0.01). Sperm telomere length was positively correlated with motility, viability and membrane integrity, and it was negatively correlated with sperm anomalies. Furthermore, Percoll gradient selected sperms with higher T/S ratio than unselected sperms (1.19 ± 0.02 vs 0.67 ± 0.03). These results suggest that sperm telomere length can be used as a new marker of bovine semen quality.