Application of Nanopore Sequencing for High Throughput Genotyping in Horses

Simple Summary Detection and genotyping of genetic variants across genomes has several applications that include, e.g., identification of genetic background of phenotypic traits, detection of disease-related variation, and analysis of population genetic structure. In this study, we attempt to develop a Nanopore sequencing-based genotyping strategy (with MinION system from Oxford Nanopore) that allows simple and cost-efficient genome-wide analysis in horse species. With this method, we generated 28,426 polymorphisms that were genotyped with high accuracy, with a level of error not exceeding 3%. The method can be further improved to increase the number of detected variants and improve their reliability by increasing the sequencing depth. Nanopore sequencing is a third-generation biopolymer sequencing technique that relies on monitoring the changes in an electrical current that occur as nucleic acids are passed through a protein nanopore. Increasing quality of reads generated by nanopore sequencing systems encourages their application in genome-wide polymorphism detection and genotyping. In this study, we employed nanopore sequencing to identify genome-wide polymorphisms in the horse genome. To reduce the size and complexity of genome fragments for sequencing in a simple and cost-efficient manner, we amplified random DNA fragments using a modified DOP-PCR and sequenced the resulting products using the MinION system. After initial filtering, this generated 28,426 polymorphisms, which were validated at a 3% error rate. Upon further filtering for polymorphism and reproducibility, we identified 9495 SNPs that reflected the horse population structure. To conclude, the use of nanopore sequencing, in conjunction with a genome enrichment step, is a promising tool that can be practical in a variety of applications, including genotyping, population genomics, association studies, linkage mapping, and potentially genomic selection.

Automated summary

A genotyping strategy based on Nanopore sequencing was developed for simple and cost-efficient genome-wide analysis in horses. The method generated 28,426 highly accurate polymorphisms, which can be improved by increasing sequencing depth.