Species Structure in Humulus Lupus (Hops)
Guest Author - Dr. Daniela Vergara
(Cornell AgriTech Cooperative Extension)
Here is a quick recap of the relationship between individuals from the species Humulus lupulus -hops. As you, beer drinkers, probably know, the female inflorescence (cone) from hops is one of the main ingredients in beer. The species H. lupulus has different groupings that come from several parts of the world. In other words, the different groups (lineages) within the species H. lupulus differ in the degree of relationships with one another.
In 2006, Murakami and collaborators decided to establish the relationships between wild H. lupulus from different places in the world. They collected 149 individuals from Europe, Asia, and North America (Canada and the US). To understand how were these H. lupulus individuals related to each other, and whether some are closer than others, they sequenced (determined the letters of) specific places in the DNA (genetic material) of these individuals. The genomic regions used were part of the chloroplast (the chloroplast is that organ in the plant cell used for photosynthesis and has DNA of its own), and of the nucleus.
They found that the North American hops from Canada and the US are very closely related, and that the European individuals were closely related among them. The European hops have two groupings, those that are found on the Caucasus region, and those from the rest of Europe. However, North American individuals are more closely related to those from Asia than to those from Europe.
My favorite discussion point of this research project was the origins of hops. It has been suggested that hops originated in China (Neve 1991), which according to Murakami et al., if this is true, then there must have been migration between the different continents, approximately 0.46-0.69 million years ago. This hypothesis of hops migrating between continents, makes sense to me, as I found through this obscure source called google, that very ancient cultures from today’s Iran and Israel used beer as far back as 8,500 BC. I hope that you, beer-drinking friends, let me know whether my googling skills regarding the history of beer are accurate.
Dr. Daniela Vergara is a member of the Cornell Cooperative Extension, the founder and director of the non-profit organization Agricultural Genomics Foundation with a widely-listened podcast ‘Cannabis Science Today’ (@cannabis_science_today). Follow Dr. Vergara on twitter @CannaBacana or connect on LinkedIn.
References
Murakami, A., P. Darby, B. Javornik, M. S. S. Pais, E. Seigner, A. Lutz, and P. Svoboda. 2006. Molecular phylogeny of wild hops, Humulus lupulus L. Heredity 97:66-74.
Neve, R. 1991. Hops. Chapman and Hall. London, England.