Equine Genetic Genealogy: Family Number / MtDNA Type Cross-reference

Pedigree Matters

Deep-Rooted Anomalies in
Female Families

Mapping the Thoroughbred
in the Equine Mitochondrial Tree

TB Mitochondrial DNA

Mitochondria are the 'power plants' of the cell, the only organelles within it that are capable of independent reproduction. Inside each mitochondrion is a single, circular chromosome that is inherited only from the mother, therefore is effectively non-recombinant i.e., changes only by spontaneous mutation.  Such mutations that accumulate within a species over the course of many millennia result in diffentiation that defines matrilineally related groups large (clades aka: haplogroups), smaller (sub-haplogroups), and smallest (haplotypes), as well as potential functional variation between groups, making mtDNA typing a useful tool for studying various aspects of the Thoroughbred horse. 

In terms of quantity of the mitogenome sequenced, sample number, and pedigree information, no purpose of such study has greater need than that of assessing the accuracy of the stud book matrilineal record. Due primarily to the expense involved in mtDNA typing, no single source available at present completely fulfills that need. So the family/mtDNA type cross-reference below integrates information from many sources, though we especially wish to express our gratitude for that provided by Performance Genetics.

It was inevitable that mtDNA typing would prove that some errors have crept into matrilineal records spanning more than three centuries during which the Thoroughbred spread far and wide from its point of origin.  More remarkable, and an enduring testament to the earliest compilers of the General Stud Book, is the extent to which so many Thoroughbred female families have clearly conserved the same mtDNA type since the foundation era.

English & Half-Bred Families American Families Colonial Famlies

Lowe/B-Z families/branches sampled.
Red - anomalies documented by findings from two or more samples of the lineage..
Expected mtDNA haplotype
* type not yet fully defined
MRCA = Most Recent Common [matrilineal] Ancestor by stud book record of samples typed. Where unambiguous evidence of error has been found, the earliest and latest dams at which evidence to date indicates it could have entered the record are named below.
1, all branches N2a MRCA - Bonny Lass (GB 1723)
1-o I2a or I2a1 Error at/after Lady Atheling (GB 1890), at/before a 1994 AUS mare
1-u L3a1b Multiple errors possible, one perhaps as early as Maid of the Glen (GB 1858).
1-w L2b1 or L2b1a Error at/after Godetia (GB 1929) at/before Monsoon (GB 1941)
2, 2-b, 2-c, 2-d, 2-e, 2-f, 2-g, 2-h, 2-i, 2-j,
2-l, 2-m, 2-n, 2-o, 2-r, 2-s, 2-t, 2-u, 2-w
L4 MRCA - Chesnut Thornton (GB 1705c)
2-a I2a2 Reported by Bower et al. 2012b. Pedigree(s) unspecified.
2-c I2a2 Error at/after Dido (GB 1830), at/before Scotch Verdict (USA 1960)
2-d L2b1 or L2b1a Error at/after Elope (USA 1919), at/before Danger Ahead (USA 1946)
2-f L1a Error at either Persian Maid (GB 1947) or her dam of record, Aroma (GB 1938).
3, 3-a, 3-b, 3-d, 3-e, 3-g, 3-h, 3-i, 3-j, 3-l, 3-m, 3-n, 3-o L2b1a MRCA - Mare (GB 1735c) by Bartlett's Childers out of Sister 1 to True Blue
3-c A1a + 9479T>C Error at/after Snapdragon (GB 1759), at/before Coterie (GB 1862)
4-b, 4-c, 4-d, 4-e, 4-f, 4-g, 4-h, 4-i, 4-j, 4-k, 4-l, 4-m, 4-n, 4-r I2a1 MRCA - Sister (GB 1722) to Guy by Greyhound.
4-i L2a2* Error at/after Duchess of Marlborough (GB 1928), at/before Cool Control (USA 1973)
4-o L2a2* MRCA of 4-o & 4-p samples - Othethea (GB 1772).
MRCA of 4-o samples - Seakale (GB 1835)..
MRCA of 4-p samples - Kate Dayrell (GB 1863).
4-p A1a + 9479T>C
5, 5-a, 5-b, 5-c, 5-d, 5-e, 5-i, 5-j B1a MRCA - Ebony (GB 1728)
5 L2b1 or L2b1a Error at/after Defiance (GB 1816); at/before Chand Beebee (GB 1890)
5-b L3a1* Error at/after Sister (GB 1838) to The Gigler by Tomboy, at/before Macedonienne (FR 1913)
5-f L2a2* Error at/after Mare (GB 1750c) by Young Cartouch; at/before La Grisette (IRE 1915)
5-g, 5-h D1b Error at either Miss West (GB 1777) or her dam. See Deep Rooted Anomalies in Female Families.
6 (6-x) L2a2* MRCA - Starstream (USA 2005).
6-a (6-a1) L2a2* MRCA of all 6-a (6-a1) samples -  Sister (GB 1728c) to Cato by Croft's Partner
MRCA of L2a2* samples - Mare (USA 1833) by Stockholder
MRCA of L3a1b samples - Murcia (GB 1864)
See: Deep Rooted Anomalies in Female Families
6-a (6-a1) L3a1b
6-b, 6-c, 6-d, 6-f M2 MRCA - Horatia (GB 1758). See Deep Rooted Anomalies in Female Families.
6-e L3a1b Error at/after Fenella (GB 1869), at/before Gondolette (GB 1902).
7, all branches L3a1a MRCA - Pyrrha (GB 1771)
7-f H Error at Messaline (GB 1923) or her dam Monisima (IRE 1910)
8, all branches L3a1b MRCA - Mare (GB 1695c) by Byerley Turk
8 N1 or N1a Error at/after Honeydew (GB 1850); at/before a 1994 USA mare.
9, 9-a, 9-e, 9-f, 9-g, 9-h G2 MRCA - Mare (1695c) by Curwen's Spot
9-b, 9-c L1a Error at either Sister to Sloven (GB 1728) or her dam of record, Sister Two (GB 1706c) to Mixbury. See Deep Rooted Anomalies in Female Families.
10, all branches L2a2* Mare (GB 1765c) by Snap
11, 11-a, 11-c, 11-d, 11-e, 11-f, 11-g I2a1 MRCA - Sister (GB 1743) to Regulus
11-g N2a Error at/after West Country Lass (GB 1846), at/before Bebop (FR 1957)
12, 12-g I2a2 MRCA - Spilletta (GB 1866). See Deep Rooted Anomalies in Female Families.
12-a, 12-c, 12-d, 12-e, 12-f L1a MRCA - Sister (GB 1723c) to Sampson by Greyhound. See Deep Rooted Anomalies in Female Families.
12-b A1b MRCA all 12-b samples - Mare (USA c1766) by *Jack of Diamonds - *Diana (GB 1754)
MRCA A1b samples - Mare (USA 1835c) by *Tranby)
MRCA I2a or I2a1 samples  - Young Maid of the Oaks (USA 1817)
12-b I2a or I2a1
13, all branches I2a1 MRCA - Milbanke's Black Mare (GB 1705c) by Makeless
13-a B1a Error at Ohiwia (NZ 1919) or her dam Wairakau (NZ 1901)
13-a L2b1 or L2b1a Error at/after Dryad (NZ 1887), at/before Lexington Pride (NZ 1983)
14, all branches L2b1 MRCA - Boadicea (GB 1807)
15-a L2b1a MRCA all 15-a & 15-d amples - Flying Whig (GB 1715)
MRCA all 15-a samples - Barbara Young (GB 1842; Flying Whig > Amorett)
MRCA all 15-a L2b1a samples - Close Comfort (USA 1979; Barbara Young > Amy Scott)
15-a N2 - single sample (IRE 2012; Barbara Young > Gondoline)
15-d L4 - single sample (USA 2014; Flying Whig > Sachrissa)
15-a N2
15-d L4
16, all branches L3a1b MRCA - Mare (GB 1823) by Don Juan
16 N2, I2a2 Multiple errors downstream of Furze Chat (GB 1862)
16-c I2a or I2a1 Error at/after Mint Agnes (GB 1904), at/before Tide Time (GB 1940)
17 L1a MRCA - Cousette (NZ 1945)
17-b L3a1a MRCA - The Gem (GB 1851)
18, 18-a A1a MRCA - Miss Windsor (GB 1754)
18 N2 Error at/after Merliton (GB 1768), at/before Flora McIvor (AUS 1834c)
18 L2b1 or L2b1a Error at/after Emily (AUS 1840), at/before Lady Gertrude (NZ 1882)
19, all branches H MRCA - Tuberose (GB 1772)
19-c L4 Error at/after Silver Wing (GB 1887), at/before Air Lassie (NZ 1929)
19-c I2a2 Error at/after Vanity (GB 1859), at/before Light Link (GB 1973)
19-c L2b1a Error at/after Merry Dancer (GB 1955) at/before First Bloom (GB 1969)
20, all branches I2a2 MRCA - Mare (GB 1765c) by Locust
20 L3a1b Error at/after Black Betty (USA 1919), at/before Roman Matron (USA 1941)
20 M2 & A1a MRCA of M2 and A1a samples - Mare (USA 1813) by *Speculator.
MRCA of M2 samples - Now What (USA 1937; Speculator Mare > Mary Bedford)
MRCA of A1a samples - Sister Leona (USA 1940; Speculator Mare > Brownlow)
21, 21-a B1b MRCA - Sister to Bandy (GB 1731)
21 L2a2* Error at/after Lady Chesterfield (USA 1801), at/before Bourbon Lass (USA 1914)
22, all branches L3a1a MRCA - Canary Bird (GB 1806).
23, 23-a, 23-b M1a MRCA - Brocklesby (GB 1721)
23-b I2a Error at/after Judith (USA 1843), at/before Lizzie G. (USA 1867)
24 I2a or I2a1 MRCA all samples - Maiden (GB 1770)
MRCA I2a or I2a1 samples - Miss Flat (NZ 1865; Maiden > Matron)
A1d - single sample (AUS 2015;  Maiden > Sister to Challenger)
24 A1d
25 N1 MRCA - Lardella (GB 1780).
26 B1a MRCA - Parsley (GB 1786)
27, 27-a L1a MRCA - Mare (GB 1751c) by Babraham
28 L2b1 or L2b1a MRCA - Ancaster Dizzy (GB 1741)
29 Q single sample (AUS 2012)
31 B1a MRCA - Mare (GB 1746c) by Blaze
32 I2a or 12a1 MRCA all samples - Nimble (GB 1784)
MRCA I2a or I2a1 samples - Miss Holborn (AUS 1969; Nimble > Nutmeg)
L2a2 - single sample (AUS 2016; Nimble > Nike)
32 L2a2
34 B1a MRCA - Bourbon Lass (NZ 1963)
36 N2 single sample (USA 2010)
37 A1a + 9479T>C MRCA - Melrose (GB 1845)
38 D1b Single archaeological sample; remains of Pot8os (GB 1773)†. Family extinct in tail female.
40 I2* Single sample
42 L2a2 MRCA - April View (IRE 1949)
52 L3a1b MRCA - Portion (IRE 1888)
B3 L3a1b (+15563A>G, 15651A>G) MRCA undetermined; pedigree known for only one sample.
B4 L3a1a (15771@) Reported by Bower et al. 2012b. Pedigrees unspecified.

†The Pot8os sequence is included with the gracious permission of the National Horseracing Museum at Newmarket and Alison Schwabe.

Published sources consulted additional to the relevant stud books:
Achilli A, Olivieri A, Soares P, Lancioni H, Kashani BH, Perego UA, Nergadze SG, Carossa V, Santagostino M, Capomaccio S, Felicetti M, Al-Achkar W, Penedo M C, Verini-Supplize A, Houshmand M, Woodward S R, Semino, O, Silvestrelli M, Giuliotto E, Pereira L, Bandelt H J, Torroni A: Mitochondrial genomes from modern horses reveal the major haplogroups that underwent domestication. PNAS USA. 2012 Feb 14;109(7):2449-54

Bobinski, Capt. K, and Count S. Zamoyski. Family Tables of Racehorses. London. J A Allen. 1953.

Bower M A, Campana M G, Nisbet R E R, Weller R, Whitten M, Edwards C J, Stock F, Barrett E, O’Connell T C, Hill E W, Wilson A M, Howe C J, Barker G, Binns M. Truth in the bones: Resolving the identity of the founding elite thoroughbred racehorses. Archaeometry. 2012[A]. doi:10.1111/j.1475-2012.00666.x

Bower M A, Whitten M, Nisbet R E R, Spencer M, Dominy K M, Murphy A M, Cassidy R, Barrett E, Hill E W, Binns M. Thoroughbred racehorse mitochondrial DNA demonstrates closer than expected links between maternal genetic history and pedigree records. J Anim Breed. Genet. 2012[B]. doi:10.1111/j.1439.0388.2012.01018.

Harrison, F. Early American Turf Stock 1730-1830 (two vols.). Richmond. Old Dominion Press. 1934.

Hill E W, Bradley D G, Al-Barody M, Ertugrul O, Splan R K, Zakharov I, Cunningham E P. History and integrity of thoroughbred dam lines revealed in equine mtDNA variation. Anim Genet. 2002 Aug;33(4):287-94.

Lowe, C B, (W. Allison, ed.). Breeding Racehorses by the Figure System. The Field and Queen (Horace Cox) Ltd., UK.

Peng MS, Fan L, Shi NN, Ning T, Yao Y-G, Murphy RW, Wang WZ, Zhang YP. DomeTree: a Canonical Toolkit for Mitochondrial DNA Analyses in Domesticated Animals. Mol Ecol Resour. (2015)DOI: 10.1111/1755-0998.12386

Rogers, B. Finding Tregonwell’s Natural Barb Mare. Bluebloods. Oct., 2014:30-35.

Roger, Byron. CEO, Performance Genetics. Personal communications 2017-2022.

2023 Judy Baugh