Taming the dragon: genetic variation in wild and domesticated Antirrhinum majus

Sean Stankowski, Hilde Schneemann, Apollonia Palmer, David Field, Nick Barton

Domesticated species and their wild relatives provide powerful case studies for examining the
processes that shape rapid diversification. Here, we conduct a population genetic analysis of
31 domesticated varieties and 33 natural populations of the common snapdragon, Antirrhinum
majus, a species in which closely related flower colour varieties form hybrid zones and display
extensive variation in floral colour and patterning. We find that domesticated snapdragons
form a single genetic group, suggesting that these lines were derived from the same set of
ancestral founders. Despite their strikingly diverse flowers, domesticated snapdragons show
substantially lower genetic diversity compared to wild populations. Genetic markers strongly
associated with known colour loci in wild populations show only weak associations across
domesticated lines. This may be because recombination during selective breeding has
weakened associations between casual mutations and linked markers, and/or because
different mutations control colour variation in domesticated snapdragons.