Hops Session
William A Deutschman, Westminster College, Salt Lake City, UT, USA
Co-author(s): Julie Kilpatrick and Brian Avery, Westminster College, Salt Lake City, UT, USA
ABSTRACT: It is important for hop breeders, growers, and
brewers to be able to accurately distinguish hop varieties. Here, we
report the use of high resolution melting (HRM) of DNA fragments to
identify and differentiate DNA microsatellite sequences from various hop
strains. HRM is a PCR based technique that allows for the
identification and differentiation of closely related DNA sequences that
may differ in sequence by as little as a single base. HRM monitors the
fluorescence of a dye that binds specifically to double stranded DNA and
therefore can precisely measure the fraction of a sample that is
annealed at any given temperature. HRM analysis is then based on the
melting temperature profile of a PCR product, which depends both on the
length and specific DNA sequence of that product. Thus, different
products that are identical or nearly identical in length and cannot be
distinguished by gel-based analyses can be easily discriminated using
HRM. We performed HRM on 10 commercial hop cultivars and 3 native hop
samples from northern Utah. Multiple primer pairs were used to amplify
different microsatellite regions in order to assess the discriminatory
power of each microsatellite region. Our results show that the HRM
technique can differentiate between microsatellite alleles that were
previously scored as being identical using gel-based detection methods.
Thus, HRM shows great promise as a fast technique with stronger
resolving power than traditional methods for identification or
verification of hop cultivars. The goal of our work is to take advantage
of the benefits of HRM to establish a broader DNA based scheme for
cultivar identification that will be of use to hop breeders, growers,
and brewers.
William Deutschman earned his Ph.D. degree in
chemistry in 2001 at the Institute of Molecular Biology at the
University of Oregon. From 2001 to 2006, he taught biochemistry at
Plattsburgh State University in Plattsburgh, NY. In 2006, he moved to
Westminster College in Salt Lake City, where he currently teaches
chemistry, biochemistry, and brewing science, while also pursuing
research projects with undergraduate students in the areas of brewing
and fermentation science.
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