Italian study shows power of DNA analysis to confirm studbook accuracy

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An Italian study has shown the ability of mitochondrial DNA surveys to test pedigree authenticity in horse breeds.

Such surveys provide an opportunity to improve the monitoring and management of livestock populations, the study team said.

Andrea Giontella and her colleagues at the University of Perugia, writing in the journal Animals, say their work shows the usefulness of mitochondrial DNA analysis in revealing the maternal legacy among samples, and whether studbook records are correct.

Mitochondrial DNA is passed only through maternal lines.

The researchers focused on the Maremmano horse. It 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, recording 440 dams and four sire founders.

For their study, the researchers selected the the most significant maternal lines in terms of offspring (for a total of 74 lineages and 92 Maremmano horses) and analyzed their mitochondrial DNA.

“We found a high variability, reflecting the importance of this local breed as a genetic resource to be preserved,” they reported.

Through multiple sampling, they then verified the pedigree information for 12 dam lines by matching genealogical data with 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,” the study team reported.

The mitochondrial data and pedigree records were in agreement for the other nine lineages explored.

The research, they said, showed that combining genealogical and historical information with molecular techniques can help in preventing errors in pedigree data and the loss of the genetic diversity of local breeds.

“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.”

“A studbook is not always error-free, therefore mitochondrial DNA analysis can provide genetic information about the maternal lines.

“The mitochondrial DNA analysis provides breeders with the opportunity to confirm the ancestry of their horses and could be used to prevent possible frauds in falsifying the genealogical data.

“This research,” they wrote, “can be considered as a preliminary study for further analyses focused on verifying the reliability of pedigree data for the remaining Maremmano dam lines and can be also extended to other local breeds and species.”

Thanks to accurate genealogical analysis, 16,588 Maremmano horses registered in the studbook were better identified, and male and female ancestors were traced, they said.

“From the reconstruction of sire and mare lineages, it was confirmed that all Maremmano horses derive from 4 males and 440 dam founders, of which 332 mares were born between 1960 and 1975.”

The full University of Perugia study team comprised Giontella, Irene Cardinali, Hovirag Lancioni, Samira Giovannini, Camillo Pieramati, Maurizio Silvestrelli and Francesca Maria Sarti.

Giontella, A.; Cardinali, I.; Lancioni, H.; Giovannini, S.; Pieramati, C.; Silvestrelli, M.; Sarti, F.M. Mitochondrial DNA Survey Reveals the Lack of Accuracy in Maremmano Horse Studbook Records. Animals 2020, 10, 839.

The study, published under a Creative Commons License, can be read here.

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