Whole genome sequencing of Red Chittagong Cattle (RCC) cattle and insight into genetic variants in candidate genes for disease resistance

Abstract

Detection of genome-wide genetic variation is one of the primary goals in bovine genomics. Genomes of several cattle breeds have been sequenced so far to understand the genetic variation associated with important phenotypes. Red Chittagong Cattle (RCC) is a locally adopted and disease-resistant indicine cattle breed in Bangladesh. In this study, we describe the first genome sequence of the RCC breed and in silico analyses of identified functional variants. Deep sequencing of a RCC bull genome on the NanoBall sequencing platform generated approximately 110 Gb paired-end data, resulting in 31X of genome coverage. Quality filtering retained 360,711,803 paired-end reads. Of the filtered reads, 99.8% were mapped to the bovine reference genome (ARSUCD1.2). A total of 17. 8 million Single nucleotide variants (SNVs) and 2.1 insertions and deletions (INDELs) were identified in the RCC genome. Ts/Tv ratio was computed and found to be 2.21. In total, 332 4621 variants were novel compared with dbSNP data (NCBI dbSNP bovine build 150). Functional annotation identified 54961 SNVs exonic regions, 63.75% of which were synonymous, whereas 30.42% were non-synonymous changes. The percentage of coding INDELs was 0.25% (Frameshift deletion 0.19% and Frameshift insertion 0.06%). We identified 120 variants in 26 candidates for five diseases-foot and mouth disease (FMD), Mastitis, Parasite, para-tuberculosis, and tick. Of the 120 variants, 50 were non-synonymous / frameshift (NS/FS), while 70 were synonymous/non-frameshift (SS/NFS). The identified catalog of genomic variants in RCC may establish a paradigm for cattle research in Bangladesh by filling the void and providing a database for genome-wide variation for future functional studies in RCC.