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MSU Fingerprinting Facility

Fingerprinting Facility

at Michigan State University


Isozyme Electrophoresis



The MSU Potato Breeding and Genetics program has a potato variety identification service via isozyme electrophoresis that has been in operation since 1990. A fingerprint database is maintained with over 200 varieties. This variety fingerprint method is rapid, economical, and accurate. In addition, either leaf or tuber tissue can be used for the analysis.

The laboratory protocol is based upon research of D. S. Douches and K. Ludlam (1991, American Potato Journal 68:767-780). Standard horizontal starch electrophoresis is employed. To facilitate the interpretation of the banding pattern of the variety, duplicated samples are run side by side on the gel. Following electrophoresis, the isozyme banding patterns are resolved via enzyme-specific stains. The discrete bands for each isozyme locus are transcribed to a database for sorting. Usually 10 loci are scored to discriminate the varieties. The summation of the electrophoretic pattern for these 10 loci is referred to as its fingerprint.



isozyme1

    isozyme2



Simple Sequence Repeats


The limitations requiring the use of fresh tissue for isozyme fingerprinting are removed by using a DNA-based system.  DNA can be isolated from various fresh and freeze-dried tissue samples and isolated DNA samples can also be archived for extended storage.  Freedom from fresh tissue also facilitates transportation of material across country borders that can be restricted due to phytosanitary regulations.

Simple sequence repeats (SSRs or microsatellites) are tandemly repeated short oligonucleotide sequences that are flanked by conserved DNA sequences.  SSRs can provide a reliable, efficient, and applied DNA-based fingerprinting system for potato.  An example of its use is shown below.  The use of this fingerprinting method is described in the journal article:

Coombs, J. J., L.M. Frank, D.S. Douches.  2004.  An applied fingerprinting system for cultivated potato using simple sequence repeats.  Amer. J. Potato Res.  81: 243-250.


SSR1



SSR2



SSR3



Please contact: Dr. David Douches for further information about these services.
Crop and Soil Science Dept.
Plant and Soil Science Building
Michigan State University
East Lansing, MI 48824
(517)355-0271x198

e-mail:  douchesd@msu.edu