Genes Involved in Anthocyanin Synthesis

Have you ever wondered why we have red and white wines? I found a really good research paper that explained this phenomenon almost a year ago and then I fell into a rabbit hole. I needed to explain first, why we have red grapes, and it took me a few blogposts to get there.
In my previous blogpost Why Do We Have White Grape Varieties?, I wrote that white grapes appear to lack anthocyanins because they did not express UFGT (UDP glucose-flavonoid 3-o-glucosyl transferase). Then, I finished the post with a cliff hanger. In 1996, when Boss et al.,¹ did their seminal experiments they didn't really know the underlying genetic reasons why white grapes did not contain anthocyanins in their skins.
Ten years later in 2006, Lijavetzky and fellow collaborators answered the question in their research paper titled Molecular genetics of berry colour variation in table grape.²
The Role of Transcription Factors
To get a handle on what they did, requires some knowledge of transcription factors. The Wikipedia defines a transcription factor as a protein that controls the conversion of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence.(For a really good explanation on transcription factors check out Khan Academy on Transcription Factors.)
Two groups of transcription factors called MYB and bHLH are the main regulatory genes associated with the control of anthocyanin biosynthesis in plants. In 2014, Huang et al. mapped out that phylogenetic tree for the MYB transcription factors involved in the phenylpropanoid pathway.³

In the diagram shown above, the main character implicated in anthocyanin production in the grape berry skin is the gene called VvmybA1 located on chromosome 2.⁴ The details of the investigation into how the gene VvmybA1 is responsible for color will sadly, need to be postponed for another blogpost. Please stay tuned, it's pretty cool.
References:
1. Boss P, Davies C, Robinson S (1996b), "Expression of anthocyanin biosynthesis pathway genes in red and white grapes", Plant Mol Biol, 32:565 - 569.
2. Lijavetzky et al., Molecular genetics of berry colour variation in table grape, 2006, Mol. Genet. Genomics, 2006: 427-435.
3. Yung-Fen Huang, Sandrine Vialet, Jean-Luc Guiraud, Laurent Torregrosa, Yves Bertrand,Veronique Cheynier, Patrice This and Nancy Terrier, A negative MYB regulator of proanthocyanidin accumulation, identified through expression quantitative locus mapping in the grape berry, New Phytologist, (2014) 201: 795–809 doi: 10.1111/nph.12557.
4. A Fournier-Level, T Lacombe, L Le Cunff1, J-M Boursiquot1, and P This, Evolution of the VvMybA gene family, the major determinant of berry colour in cultivated grapevine (Vitis vinifera L.), Heredity (2010) 104, 351–362; 18 November 2009, doi:10.1038/hdy.2009.148.