The earliest grape varieties were probably all red.
The very first original varieties that gave rise to the “founder varieties” (Pinot Noir, Gouais Blanc, and Savagnin) were probably all red. Scientists think that the first white variety was a mutation that occurred when pieces of DNA moved within the gene, interrupting the coding for anthocyanins, molecules in grape skins that create color. In early wine-drinking civilizations, the rarity of white wines gave them social value and led to the perception that white wines were more refined than reds, and as such, more desirable as upper-class drinks. For their part, early on, the founder varieties crossed with each other and with scores of other varieties (some of which no longer exist) to create scores of varieties we drink today from Chardonnay and Riesling to Blaufrankisch, Gamay, and Muscadelle.