Pedigree Query

Previously, we identified HG Tb as a signature of the Turkoman horse, an ancient horse population from the steppes of central Asia23. During the past 300 years HG Tb was extensively spread by the English Thoroughbred. The Thoroughbred sire lines trace back to three founder stallions that were imported to England at the end of the 17th century10,64. Here, we fully resolved the heritage of the Thoroughbred sire lines with MSY haplotyping. The haplotype structure of 65 males was highly consistent with their paternal genealogy inferred from the pedigree (Fig. 3). We now clearly discriminate discrete sublines of Darley Arabian, born in 1700 (Tb-d) and Godolphin Arabian, born in 1724 (formerly Tb-g, now Tb-oB3b). The third founder, Byerley Turk, born in 1680, was newly characterised by an allelic variation of the tetranucleotide microsatellite fBVB (GATA14/GATA15; Supplementary Table S8) that defines the Tb-oB1 clade. According to pedigree information only few of the tested males trace back paternally to Byerley Turk. We thus screened a representative dataset of 109 purebred males by genotyping fBVB and detected allelic variation of fBVB only in Tb clade horses (Supplementary Table S9). All 30 patrilineal descendants that coalesce in Herod, born in 1758, whose ancestry in turn traces back to Byerley Turk, carried the Tb-oB1 specific allele 208 (Supplementary Table S9). We also confirmed Tb-oB1 in eleven horses tracing back to St. Simon, born in 1881. According to stud records, St. Simon was the son of Galopin, born in 1872, who was sired by Vedette, born in 1854. The line should trace back to Eclipse, born in 1764 (Fig. 3) according to stud books. All descendants of St. Simon carry Tb-oB1, undoubtedly the HT of Herod (Fig. 3), and not that of Eclipse (Tb-dW*). Thus, an incorrect paternity assignment must have occurred in this lineage. In a discussion recorded in the early to mid 19th century, one party claimed that instead of Vedette a moderate performer named Delight, born in 1863, a Byerley Turk descendant (Fig. 3b), fathered Galopin (65–67); our molecular data support this view.