English TB blood in flat racing “Arabians”
This quote in the recent DNA study led by Samantha Brooks in the journal Nature is pretty damning, I thought:
The presence of Thoroughbred-specific Y chromosome haplogroups among Arabian racehorses indicates that the large chromosomal blocks of Thoroughbred origin detected in flat racing Arabian horses are likely derived, at least in part, from crosses with Thoroughbred stallions that occurred after the emergence of the “Whalebone” haplotype in the 1800s.”
I’ve previously read the entire article and yes, I do think the genetics are pointing out the introduction of non-Asil blood to try to produce a winner. JMHO
I mean, if there are registered Arabian geldings/stallions with the Whalebone haplotype, there is a Throughbred sireline. The presence of the Byerley Turk sireline can at least still be held in contention, but while there may be a number of contentions of authenticity in Arabian breeding circles that are up in the air, this is not one of them.
Moira: are you sure that the study referred to differentiates between the Byerly Turks Y and other Thoroughbred Y chromosomes? I suspect you’ve got the wrong study here..
best
Bruce Peek
The Y chromosome haplotyping section has a comment about it. Quoted from the paper: “…Five of the race-use horses carried the Tb-oB1* haplogroup attributed to the “Byerley Turk” foundation sire of the Thoroughbred breed28. Tb-oB1* is found within a variety of breeds and lineages, including the Turkomen. Therefore, these five horses may carry Y chromosomes derived from ancestors common to both racing Arabians and the Thoroughbred breed28. However, the remaining three racing Arabian horses carried the Tb-dW1 haplogroup, also known as the Whalebone haplotype. The mutation leading to Tb-dW1 occurred around 1800 29, after the establishment of the Thoroughbred studbook, and is linked to the “Whalebone” sire line within the modern Thoroughbred breed28. Tb-dW1 is almost fixed in Thoroughbred horses and has not been reported previously in modern Arabians. The presence of Thoroughbred-specific Y chromosome haplogroups among Arabian racehorses indicates that the large chromosomal blocks of Thoroughbred origin detected in flat racing Arabian horses are likely derived, at least in part, from crosses with Thoroughbred stallions that occurred after the emergence of the “Whalebone” haplotype in the 1800s.”
This part here – “Therefore, these five horses may carry Y chromosomes derived from ancestors common to both racing Arabians and the Thoroughbred breed” – makes me so, so happy. A number of previous studies have claimed it’s indicative of Thoroughbred ancestry full stop, and I am just so glad to see careful, thoughtful statements coming out of this one.
Thank you very much for your clarification on this study, on this and a previous post. It is much appreciated! And re your comment below on the Thoroughbred introgression via damlines, that is unsurprising. I have heard rumours about some of the Crabbet horses, during Lady Wentworth’s tenure, and some of the racing Arabians as well, so it would be very interesting to tease out, as far as possible, the indisputably Thoroughbred influences on the modern Arabian.
Beth, thank you for pulling the relevant quote in answer to Bruce’s question.
I’m in agreement with Kate — it’s been quite obnoxious to see the leap of conclusion that some of these sirelines could **only** have found their way into Arabians via Thoroughbred sirelines. Something like the Whalebone haplotype is a dead ringer, but as of right now I don’t see any evidence precluding or confirming that the original Thoroughbred sirelines came from Turcomans vs Arabians. And I still find it highly suspect that the Akhal Teke is being used as a “control” for the Turcoman bloodline despite having known TB sirelines as well as a history of being bred under a government that is known to have lied about the pedigrees of their horses. Big Shrug, there.
Perhaps we can tease out the truth of Nureddin II and Sharima with this developing understanding of DNA 😛
You’re welcome, Moira – though I apologize for duplicating the information; at the time I posted the above I hadn’t seen your comment in the other thread. I also agree re: the Akhal-Teke issues. And if historical reports of (at least some) Turkmen tribes using Arabian sires in their horse breeding programs are true – what impact does that have on interpreting DNA findings?
I’m really hoping the Arabian horse community can come together and find some innovative ways to help support (financially and with samples) continued research. So much still to learn – and to figure out how to correctly interpret. 🙂
You’re welcome, Kate. I completely agree re: some of the language used in previous studies being IMHO a bit too definitive and prematurely closing the door re: potential ancestral relationships; not to mention numerous contextual issues when adding the historical record and cultural considerations into the mix. And I confess, Dr. Brooks has had to listen to quite of bit of my ‘opinion’ about this. 🙂
Just to add a quick comment to Edourad’s initial post – the TB admixture isn’t limited to just the Y chromosome work discussed in the paper. When I initially saw figure 4 I was really struck not only by the degree of admixture, but also the scope across the sampled group…the bottom third of that figure is really telling re: those ‘big blue blocks’ and strongly suggests some of the admixture coming from sire and dam contributions.
This may be a silly question, as I don’t remember if any of the sampled groups were from US Arabians. Could the TB admixture in sire or dam contributions be coming via American Saddlebred introgressions? (Hope I’m using the terms correctly)
I have read that the only “pure” Turkoman horses of this century are in Iran. Canadian Brent Seufert was trying to obtain some but that proved impossible due to the political situation IIRC.
So has anyone hypothesized as to how the Y chromosome common to both arabs and thoroughbreds got into the arabians tested? A good possibility might be that because every year literally thousands of pilgrims trudged across the cradle country deserts on their way to Mecca many of them from Turkey- Iran and the stans( nations that now make up Uzbekistan, Afganistan etc) they brought their horses with them.Their horses would have crossed areas where the Tai and Bani Lam roamed… Some of the Bedouin co- believers worked as pilgrim caravan guides and guards. Presumably not every bedouin was able to get hired on as a guide/ guard and would have continued doing what they always did to make a living namely robbing whom they pleased.. We do know that not all bedouin were purist horse breeders. It seems within possibility that after a few generations of breeding back to a purist gene pool the F 4 generation horses would have esentially looked like asil stock.
best
Bruce Peek