A refined karyotype based on an ultra-high copy 167-bp tandem repeat and ribosomal DNAs

Panax ginseng Meyer (Asian ginseng) has a large nuclear genome size of over 3.5 Gbp in haploid genome equivalent of 24 chromosomes. Tandem repeats (TRs) occupy significant portions of the genome in many plants and are often found in specific genomic loci, making them a valuable molecular cytogenetic tool in discriminating chromosomes. In an effort to understand the P. ginseng genome structure, we characterized an ultra-high copy 167-bp TR (Pg167TR) and explored its chromosomal distribution as well as its utility for chromosome identification.