Project description:Effective management and control of parasitic infections on farms depends on their early detection. Traditional serological diagnostic methods for Fasciola hepatica infection in livestock are specific and sensitive, but currently the earliest detection of the parasite only occurs at approximately three weeks post-infection. At this timepoint, parasites have already entered the liver and caused the tissue damage and immunopathology that results in reduced body weight and loss in productivity. Here, we investigated whether the differential abundance of micro(mi)miRNAs in sera of F. hepatica-infected sheep has potential as a tool for the early diagnosis of infection. Using miRNA sequencing analysis, we discovered specific profiles of sheep miRNAs at both the pre-hepatic and hepatic infection phases in comparison to non-infected sheep. In addition, six F. hepatica-derived miRNAs were specifically identified in sera from infected sheep. Thus, a panel of differentially expressed miRNAs comprising four sheep (miR-3231-3p; miR133-5p; 3957-5p; 1197-3p) and two parasite miRNAs (miR-124-3p; miR-Novel-11-5p) were selected as potential biomarkers. The expression of these candidates in sera samples from longitudinal sheep infection studies collected between 7 days and 23 weeks was quantified using RT-qPCR and compared to samples from age-matched non-infected sheep. We identified oar-miR-133-5p and oar-miR-3957-5p as promising biomarkers of fasciolosis, detecting infection as early as 7 days. The differential expression of the other selected miRNAs was not sufficient to diagnose infection; however, our analysis found that the most abundant forms of fhe-miR-124-3p in sera were sequence variants (IsomiRs) of the canonical miRNA, highlighting the critical importance of primer design for accurate diagnostic RT-qPCR. Accordingly, this investigative study suggests that certain miRNAs are biomarkers of F. hepatica infection and validates miRNA-based diagnostics for the detection of fasciolosis in sheep.
Project description:We carried out a cross species cattle-sheep array comparative genome hybridization (aCGH) experiment in order to identify copy number variations (CNVs) in the sheep genome analysing animals of Italian dairy breeds (Sarda, Bagnolese, Laticauda, Massese and Valle del Belice) using a tiling oligonucleotide array with ~385,000 probes designed on the bovine genome. We identified 135 CNV regions (CNVRs) covering about 10.5 Mb of the virtual sheep genome referred to the bovine genome (0.398%) with a mean and median equal to 77.6 kb and 55.9 kb, respectively. A comparative analysis between the identified sheep CNVRs and those reported in the cattle and goat genomes indicated that overlaps between sheep and goat and sheep and cattle CNVRs are highly significant (P<0.0001) suggesting that several chromosome regions might contain recurrent interspecies CNVRs. Many sheep CNVs affect genes with important biological functions. Further studies are needed to evaluate the functional relevance of these CNVs.
Project description:The sheep (Ovis aries) plays a major socio-economic role in the world. Copy number variations (CNVs) are increasingly recognized as a key and potent source of genetic variation and phenotypic diversity, but little is known about the extent to which CNVs contribute to genetic variation in Chinese sheep breeds. Analyses of CNVs in the genomes of eight sheep breeds were performed using the sheep SNP50 BeadChip genotyping array. A total of 111 CNV regions (CNVRs) were obtained from 160 Chinese sheep breeds. These CNVRs covered 13.75 Mb of the sheep genome sequence. A total of 22 Go terms and 17 candidate genes were obtained from the functional analysis. Ten CNVRs were selected for validation, of which 7 CNVRs were further experimentally confirmed by quantitative PCR. Four candidate genes were selected to confirm the results of the functional analysis. These results provide a resource for furthering understanding of ruminant biology, and for further improving the genetic quality of sheep breeds.