Marcher Apple Network

Marcher Apple Network

RHWYDWAITH AFALAU’R GORORAU

Reviving the Old Apple and Pear Varieties in the Welsh Marches

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.

Recently research effort on parentage has increased and borne ‘fruit’!  Notable studies by Ordidge, et al. (2018), Muranty et al. (2020) and Howard et al. (2022) has looked at about 700 varieties of diploids, triploids and a few tetraploids.  We’ve collected the results, added a few, and made them into a table available here.

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 by fruitID and MAN, Explorer-P2P, uses MS Excel on  any of 5000+ genotypes. The Tool is available at fruitID.com/#help
  • – A study comparing SSR derived parentages of 116 varieties with those found by Hélène Muranty et al. from a definitive study applying whole genome SNP DNA. Parentages were found easily for about 50%, for 40% with some uncertainty  among a number of possibilities, and for the remainder some data issues.  The list is given here (with link) for inspection
  • – A study of 274 sets of parents given in the National Apple Register was compared with suggestions from DNA fingerprints.  Of these 188 record two parents with progeny and parents having SSR (SNP).  In about 51% of the cases the records are suggested to be right.  In another 46% of cases they are wrong and in many cases alternative parents could be found that are suggested as plausible. Findings are listed in a table available for inspection.
  • – Of 864 DNA samples, some being repeats or duplicates, submitted by MAN in about 30% cases parents were identified with some degree of confidence.  You are welcome to browse MAN’s listing of suggested parents or of the mismatches which indicate no parents could be found with confidence

Recently research effort on parentage has increased and borne ‘fruit’! Notable studies by Ordidge, et al.(2018),Muranty et al. (2020) and Howard et al. (2022) has looked at about 700 varieties of diploids, triploids and a few tetraploids. We’ve collected the results, added a few, and made them into a table available here.

This investigation is work in progress and offered for comment, well, polite comment!