2008 - DNA from herbarium specimens settles a controversy about origins of the European potato.
By Mercedes Ames.
The origin of the European potato has been the subject of long debate. The most accepted theory was that "Andean" potatoes (landraces in the high Andes from western Venezuela to northern Argentina) were the sole source of early European introductions and that "Chilean" potatoes (landraces in lowland south-central Chile) were introduced into Europe only after their Andean predecessors were wiped out during the potato famine which began in the UK in 1845.
Such theories rely on inferences based on the morphology of early herbarium specimens, on the morphology of extant putative early landrace introductions from India and the Canary Islands, and historical records that are incomplete and speculative, to include data on old shipping routes, day-length adaptation, and harvest dates. Our work provides the first direct evidence bearing upon this question. Andean and Chilean genotypes can be distinguished by a 241-bp deletion in the plastid genome. After extracting DNA from a small hole-size sized samples of dried leaf tissue from early potato specimens from Europe grown between 1700 and 1910 we surveyed this plastid deletion. We found that the Andean potatoes got to Europe first, but that Chilean potatoes were starting to get popular there fully 34 years before the late blight epidemic, and Andean potatoes persisted as late as 1892 in Europe, long after this epidemic.
Ames, M. and D.M. Spooner. 2008. DNA from herbarium specimens settles a controversy about origins of the European potato. Amer. J. Bot. 95: 252-257.