Viney, two questions if you have the patience:
How does one research the mare family for a given horse?
Would you please characterize the Neartic tsunami a bit more? I assume this was not said as a good thing happening, but I’d like to understand it a but more.
And I apologize if everyone else reading this knows the answers except for me!
Nearctic tsunami–Before Nearco and Lady Josephine, both of whom spread their genes very widely, the C variant of MSTN gene was thought to be in approximately 10% of all TBs. It was not present in any of the great sires of the past whose DNA was sequenced from remains that were preserved. In at least one of the genetic studies of TBs on the T/C gene, it was pointed out that the descendants of Nearctic (Nearco sire) are far more likely to carry that allele than the other descendants of Nearco, like Nasrullah and Royal Charger (who, BTW, did extremely well on the NA mare base, which may have come from their descent from Lady Josephine.) Nearctic, of course, is the sire of Northern Dancer who may be the most heavily used TB sire in all of history. So before Nearctic, it was very likely that a TB would be either T/T, T/C, or C/T. Now the C/C variant is showing up in over 50% of modern TBs. It’s my personal belief that the C variant was far more common in North American racing lines than in European ones just because we have many Non-GSB horses back in the depths of our history. Nearctic literally changed the breed by passing on a gene that produces a proclivity for precociousness and short distance. This becomes clear from the genetic work done by Emmeline Hill and some of the other European researchers. It’s founded in the discovery of the gene and statistical studies of its effects. So when Nearctic came to North America and met the North American mare base, if he actually WAS a C/C, he passed his C on in a population that was far more likely to already have a C to meet his. Its also worth noting that export of North American mares to Europe and the UK was inhibited for at least half a century by the Jersey provisions of the British Jockey Club which refused to accept horses with ANY non-GSB blood as full TBs. If a horse with non-GSB blood had descendants who were already in the GSB, those lines were grandfathered in–which is why Lady Josephine and Nearco’s dam (and Orby and Tourbillon) could produce GSB horses. There is a very long history behind all this. The US and Canada got the Brits to revoke the Jersey Act in the 1950’s, so North American TBs with very long histories of “pure NA TB” were allowed to breed full GSB descendants. That’s when the export traffic started going in both directions.
How to research mare families–If you click on a mare on Pedigree Query and ask for her progeny, it will show the family numbers. Then go here:
http://www.bloodlines.net/TB/Families/FamilyNumbers.htm and start exploring. Another good place to look is here:www.tbheritage.com
Aah, Viney - with all due respect - that post above had my eyes glazed over. All I can say, is thank goodness we have you to refer to, but I need it in simpler terms. We are very lucky to have a poster with your depth of knowledge. 
But my horse has lots of these horses in her pedigree, which is what I wanted.
Thanks viney!
4-m is the family that came up most solid when I started following paths around Sadler’s Wells and Dynaformer.
Interesting about the Nearartic tsunami too, because there were a few paths I went down where I noted “no Nearco” especially in German-bred horses.
Viney, thank you so very much.
Have you written a book on this subject for sport horse enthusiasts yet? I hope you have or will.
One of the reasons that I think the C allele of the MSTN gene was far more common in North America than in Europe from beginning is that 90+% of QHs are C/C. QHs share many of the Non-GSB ancestors with the old North American TBs (who as we all know as been described by some as “North American running horses” and not “really” TB at all.) Some of the non-GSB breed founders in both NA running horses and Colonial short track horses are also found in Hastings and Nearco and Lady Josephine and quite a few other very widely used TBs. Some were Spanish Barbs.
There is been a very new study of the variants of the Y chromosome in modern Western (mostly European) horses which is also very interesting indeed. There are only five variants of that chromosome. Back in history, the domesticated horse received the primary variant; that’s the one that is common in Arabians and Spanish horses and many other breeds. From that ancestral chromosome (HT1) a variant appeared (HT2) that was widely spread by (one assumes) breeding selection. It’s the base for most WBs and the traditional TB. There is a branch of the Eclipse family that derives from Pot8os–Waxy–Whalebone that had a mutation (HT3). It was not present in Eclipse’s son, King Fergus, which is the other branch of Eclipse (St. Simon) or in Matchem or in Herod, all of whom are barely hanging on today. What we have in the TB population now is a huge majority of sires from the Whalebone tribe–up to 90%. That Y chromosome has swamped TBs, but not so much WBs. If the Whalebone Y has become so prevalent over time, there has to have been selection pressure; and the selection pressure would not exist without a reason. No one knows yet precisely what advantage HT3 gives in racing, but logically there must be one. The variant they call HT2 is said in the paper to be the most common in QHs and is the only one they found in Standardbreds. It’s racing TBs and WBs and other horses with the Whalebone sire line that have HT3.
[QUOTE=frugalannie;6929943]
Have you written a book on this subject for sport horse enthusiasts yet? I hope you have or will.[/QUOTE]
Hear hear
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