Standards for declaring and computing matching probabilities between genotypes of maize in cases where identities, pedigrees, and ownership of germplasm are in dispute

--J.S.C. Smith, B. Bowen, D. Grant. B.A. Orman, R. Fincher, and O.S. Smith

Disputes over the identity, pedigree, and ownership of lines can be very costly to resolve in respect of both monetary resources and time spent by breeders and other researchers away from the development of further improved genotypes. Methods to derive laboratory data that are repeatable and reliable would help resolve issues of genetic identity and veracity of pedigree. Acceptable testing methods could reduce both the length and the number of disputes. A decline in both the frequency and expensiveness of disputes would benefit agriculture since it would allow the concentration of more resources into independent, productive, and innovative breeding rather than their siphoning out into defensive strategic enterprises. In the field of human forensics, much valid criticism has been made of the use of DNA as evidence (Lander, Nature 339:501-505, 1989). In plants, all of the problems encountered in human forensics, i.e. lack of abundant, high quality, and uncontaminated DNA, are obviated by the usual availability of numerous seeds of each genotype. There remain, however, important lessons to be learned from the experiences that human forensic scientists have encountered. These include: 1) quality checks on DNA; 2) checks on sample identity and protection against mislabelling errors; 3) use of adequate molecular weight marker standards; 4) running of samples unmixed and mixed as final tests of band matches; and 5) the availability of a database of band frequencies that can be used to compute match probabilities.

We have prepared a document citing these various factors and including some proposals as to what should be done to evolve usable standards of procedure in the derivation of RFLP data to resolve identity, pedigree, and ownership disputes. We would like to send this manuscript to any individual or organization in order for them to be able to add any comments to its content. Therefore, we ask you to write to one of us (J.S.C. Smith, JSC) if you would like to have an opportunity to review the current proposals. A revised set of standards then could be considered for use as a means to expedite or to reduce the need for lengthy disputes over germplasm ownership. In this respect, it is very important that one or more independent laboratories be able to perform these procedures and that they have at their disposal a database of RFLP band frequencies that encompasses the most important public inbred lines and proprietary commercial hybrids. An investment by the corn industry to develop a means of rapidly solving or even preventing disputes would be very small compared to the costs that would be entailed by numerous lengthy disputes.

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors

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