DNA Parentage Investigation
Can DNA fingerprinting confirm or refute possible parentage of a variety?
The latter is true, at least for cases beyond likely experimental error. This holds true for either possible parent if their DNA is not the same as any part of the progeny’s. Practically, if a possible parent has one or more marker-pairs with alleles clearly different from those in the progeny of interest, the parentage is assessed ‘improbable’ for guarding against experimental glitches, though for all intents it is impossible.
Can it be used to confirm or even find parentage? Yes and No! The situation is much more complex. Please continue reading to appreciate the subtleties.
A detailed report is available to read here that describes six components of the investigations:
- – The principal behind comparing fingerprints of any two plausible parents with a given progeny.
- – A tool built be MAN uses MS Excel, Parent2Progeny, and enables DNA SSR fingerprints to be used quickly for any of the 3000+ fingerprints in the fruitID Explorer 5.22 database fruitID.com/#help. The Tool is available by contacting MAN.
- – A study comparing parentages of 115 varieties suggested by using Parent2Progeny with those found by Hélène Muranty et al. from a definitive study applying whole genome SNP DNA. Parentage assessed by Parent2Progeny matched about 90% of the definitive parentages. The list of detailed results and comments is given for inspection.
- – A study of 271 sets of parents given in the National Apple Register was compared with suggestions made by In about 45% of the cases, the plant breeder records are suggested to be right, and in another 45% of cases they are wrong. For those that are wrong in many cases alternative parents could be found that are suggested as plausible. Findings are listed in a tabled available for inspection.
- – 1048 DNA samples submitted by MAN, GOT, TPT and WPCS orchard groups over the last four years were investigated. In only about 15% of the cases parents were identified with some degree of confidence. It is far fewer than for either of the two previous studies. Partly this is a consequence of these two studies “creaming” off the well-defined cultivars, partly the preponderance of ‘unknowns’ in local orchard groups collections, and partly that these unknowns are likely seedlings of seedlings or of cultivars not present in the reference dataset. You are welcome to browse MAN’s listing of suggested parents or of the mismatches which indicate no parents could be found with confidence.
- – A number of cases have been found where a diploid variety is a parent to triploid in which (nearly) the entirety of parent diploid DNA is incorporated with half the DNA from a second parent to create a triploid. A case in point is Cox’s Orange Pippin DNA is entirely included into Holstein. Several examples have already been noted and are listed. Sometimes it is possible to suggest the second parent.
This investigation is work in progress and offered for comment, well, polite comment!