Paleopolyploid

Syntenic dotplot of grape versus itself. Each genomic region of grape is syntenic with two other intragenomic regions. This is evidence that grape is an ancient hexaploid. This hexaploid nature of its genome is shared with all other rosids and asterids (nearly the entire eudicot group). This analysis can be regenerated at: http://genomevolution.org/r/4p71

Ancient polyploidy or whole genome duplication events. These have usually happened long enough ago that polyploidy is unable to be determined by chromosome counts or genome size. One method to detected these are through syntenic dotplots. One famous paleopolyploidy event in angiosperms is the eudicot paleohexaploidy. In vertebrates are the two sequential tetraploidies known as 2R.