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

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.

Genetic Variability and Population Structure in the Sardinian Anglo-Arab Horse

“…A further confirmation is provided by the number of ancestors that explains the 50% of genetic variability. Comparing the results in REF2 (26), REF3_MA (13), REF_M (7) and REF_B (8), the number of ancestors used for reproduction is higher in SAA than in the other breeds, which is explained by the breeding strategies applied for this breed. Breeders of SAA are permitted to choose stallions from the three following genetic types: Thoroughbred, Anglo Arab and Sardinian Anglo Arab.…”

“…This horse breed lives in the isolated geographic context of Sardinia (an Italian island in the Mediterranean Sea) which could have had a key role in shaping its population and genetic structure. Recent studies based on horse mitogenomes have defined a complex and detailed phylogeny, describing the mutational motifs of 18 different haplogroups [ 6 ] and the mitochondrial variability of different Italian local breeds [ 7 , 8 ]. However, data at a micro-geographic level for SAA breed are still lacking.…”

Exploring the Origin and Relatedness of Maternal Lineages Through Analysis of Mitochondrial DNA in the Holstein Horse

“…Nonetheless, for 13 of the 75 analyzed lineages, the mares' mtDNA sequences differed in one to three positions. Some authors interpret the occurrence of more than one haplotype per maternal lineage as incorrect pedigree records (Kavar et al, 2002;Giontella et al, 2020). However, a small number of differences in the nucleotide sequence between mares within a lineage may be more likely caused by de novo mutations or alternate fixation of heteroplasmy.…”

A Genetic Window on Sardinian Native Horse Breeds through Uniparental Molecular Systems

“…Few stallions, producing most desirable offspring, were often crossed with local autochthonous mares resulting in a high variation among the maternal lines but a limited variability in the paternal counterpart, both at macro-and micro-geographic levels. This breeding management is reflected in the uniparental markers acquired from female (mitochondrial DNA) and male (Y chromosome) ancestors [5][6][7][8][9][10][11][12]. The striking low diversity displayed by the non-recombining region of the Y chromosome (NRY) reflects the small number of stallions that contributed to the establishment of current breeds [6,10].…”