library(vcfR)
vcf_file <- system.file("file.vcf$", package = pkg)
vcf <- read.vcfR( vcf_file, verbose = FALSE )
chrom <- create.chromR(name='Supercontig', vcf=vcf)
plot(chrom)
#MORE at https://cran.r-project.org/web/packages/vcfR/vignettes/intro_to_vcfR.html