Genetic Research Shows That Syrah is the Offspring of Pinot

A blogpost I wrote in 2013 called Cofermentation of Syrah and Viognier, contained this information:
"...Syrah and Viognier are Rhone varieties and appear to be genetic siblings."
At that time, to validate this information, I went to consult the massive compendium, Wine Grapes¹ and there it was---Syrah is the genetic offspring of Mondeuse Blanche and Dureza and one of the parents of Viognier is Mondeuse Blanche, so it looks like they are half-siblings."
Since I'm on this grape genetics kick, I wanted to go to the source, so I looked online and found that in 2006, Vouillamoz et al. published their research on French and Italian grapes and their genetic relationships.²
They analyzed 89 grape cultivars with 60 microsatellite markers (for a refresher on "microsatellite markers" please check out my blog on National Clonal Germplasm Database) in order to accurately calculate the identity-by-descent (IBD) and relatedness (r) coefficients among six putatively related cultivars.
The six cultivars they used in this study were the French varieties Pinot, Syrah and Dureza and the Northern Italian varities Teroldego, Lagrein, and Marzemino. The study wanted to determine if any of these cultivars were related.
Using the likelihood based kinship approach allowed the detection of full siblings (FS) and 21 relatives without knowledge of their parents. Parentage is most likely to be found when two cultivars share at least one allele at each locus, a pre-requisite for demonstrating a parent–offspring (PO) relationship. In order to demonstrate parentage, these shared alleles would have to be identical by descent (IBD), meaning that they are recently descended from a single ancestral allele, and not simply identical by state (IBS), which can happen by chance. In practice, only identity by state (IBS) can be scored and identity by descent (IBD) must be inferred.
The data data strongly confirmed the ‘Syrah’ parentage to consist of Dureza and Mondeuse Blanche, previously established by Bowers et al. Further, the detection of an unexpected genetic relationship between Pinot and Syrah, lead to the following relationship diagram shown below:²

In the Robinson et al. Wine Grapes bible, more detail is provided on the genetic relationship between Pinot and Syrah, as well as Viognier:¹

If it wasn't for Pinot, we would not have the ancient varieites of Dureza and Mondeuse Blanc. And if not for those cultivars, no Viognier, no Syrah!
One can imagine in an ancient field of Mondeuse Blanche, the emergence of Viognier and Syrah offspring. In a field such as this, it is not difficult to imagine that early harvesters brought in both Viognier and Syrah and began the tradition of cofermentation of the two varieties.
References:
1. J. Robinson, J. Harding and J. Vouillamoz, Wine Grapes - A complete guide to 1,368 vine varieties, including their origins and flavours, pg 1026, Allen Lane 2012 ISBN 978-1-846-14446-2.
2. Vouillamoz JF1, Grando MS., Genealogy of wine grape cultivars: "Pinot" is related to "Syrah", Heredity (Edinb), 2006, Aug;97(2):102-10.