Relative age of gene duplication using 4DTV as a proxy for time. Branches are not drawn to scale. (a) 4DTV distance between grapevine F3'5'H s. (b) Distribution of 4DTV distance between the most recently duplicated F3'5'H pairs. (c) Nucleotide positions of 4DTV between the copy F3'5'Hk and two groups of the most recently duplicated F3'5'H s. Long ticks show variable positions within either group, short ticks show transversion with respect to both groups. * Estimated according to , ** intergenic recombination.