Mitochondrial DNA Survey Reveals the Lack of Accuracy in Maremmano Horse Studbook Records

SIMPLE SUMMARY: Breed management and conservation are based on documents (pedigree) that record the relationships among animals although they are not always complete and error-free. Thanks to the DNA analysis, it is possible to check the correct genealogy and breed history. Our study focuses on the Italian Maremmano horse breed, whose Studbook was established in 1980. Starting from a selection of 74 maternal lines, we analyzed the mitochondrial DNA (which is transmitted to offspring only by mother) of 92 samples and verified the pedigree data of 12 dam lines by matching genealogical and mitochondrial information. We found some mistakes in three maternal lines, as the samples belonging to the same lineage showed different mitochondrial DNAs, thus suggesting that the information recorded in the Studbook is wrong and the samples do not descend from the same dam founder. With this research, we confirm the utility of combining genealogical and historical information with molecular techniques in order to prevent errors in pedigree data and the loss of the genetic diversity of local breeds. ABSTRACT: The Maremmano horse is considered one of the most important Italian warmblood breeds which originated from an ancient population. In 1980, the National Association of Maremmano Breeders established the first Studbook that recorded 440 dams and four sire founders. In this study, we selected the most significant maternal lines in terms of offspring (for a total of 74 lineages and 92 Maremmano horses) and analyzed their mitochondrial DNA control regions. We found a high variability, reflecting the importance of this local breed as a genetic resource to be preserved. Through multiple sampling, we then verified the pedigree information for 12 dam lines by matching genealogical data with mitochondrial haplotypes. A complete concordance was demonstrated in nine lineages, while for the other we highlighted a different number of haplotypes for each line (three in Fiorella, two in Nizza I, and two in Pomposina), thus suggesting that the information recorded in the Studbook could be wrong and the samples do not descend from the same maternal founder. Our combined analysis provides the opportunity to confirm the ancestry of animals and could be employed to prevent errors in pedigree data also for other breeds and species.