[QUOTE=NOMIOMI1;6032886]

There are plenty of successful horses from Norther Dancer as well, but that was not the point.
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He could have 1000 great sons making him number one sire and that would not erase his bad conformation.
And these stallions in the list Id pay to see just how nice the mares were that helped clean up THAT act ;)[/QUOTE]
And that was my point, well said Nomiomi1. The mares were superior because his price was kinda high so only the best mares were sent to him. But that STILL does not erase his genetic heritability to the lineage. Some of his stallion sons and grandsons are spectacular. But genes are a funny thing. Sometimes a grandson or great-grandson might not carry any of his bad genes at all and their kids will be spectacular. And another one might carry hidden (dormant) ones and you wonāt know until it shows up in a few of their kids. The point is, 50% of his kids carry the bad conformational genes and, to pick on a random number, letās say 35% of his sons carry those bad genes in a dormant fashion. Their own personal conformation is beautiful, lovely talent, and they produce pretty kids⦠say 75% of the time. Letās pick on another number, say some 15% kinda have the appearance of granddad - okay those boys are gelded, the mares not bred, and weāve successfully weeded those out. Great. Well, not so great⦠because there is STILL an unknown percent of mares and approved stallions who donāt look like granddad, but hidden in their genetic makeup are the dormant genes of everyone else in their family tree.
I would like to hear from a bonified medical geneticist - I bet they would tell you the genetic traits carry forward for a hundred generations or more. Maybe longer. The field of genetics is relatively new and there are many things we donāt know.
Horses genome are still being unravelled, but there is a guess that they carry a similar number of genes that humans do - which is 30,000. They have 32 pair chromosomes (64 all total) upon which all the various genes reside. Some are turned on and show in the physical and psychological traits of the horse. Most are dormant.
Each foal gets exactly 15,000 genes from mom, and 15,000 from dad. Then there are some markers that come along with the ride that tell the chromosomes which genes to turn on and which to turn off. Some are only turned on for a little while before theyāre turned off at a certain time - to manipulate growth factors, for example.
Letās try to do the math (not my strong suit here) ⦠if you want to trace ONE gene that tells the coracoclavicular ligament to be a tad shorter on the right side, which in turn puts enough pressure to twist the shoulder and carry it through to the toe in the hoof (I doubt it is just one gene that does it, but letās just say it does)⦠since half go to each kid⦠so kid 1 gets 1:7500 chance to get it, kid 2 gets a 1:3500 and so on⦠I got to generation 19 and the number was 0.0286102294921875⦠but thatās not an eradication. Itās a small chance, but itās still there. You keep dividing by 2 and see how far you get⦠itās infinity. You NEVER get to 0.
EACH gene you are contributing to the family tree is there FOREVER.
Granted, by the time you get to generation 19 your chances are pretty slim and most of the kids are not going to have the gene. But one always will and will always carry it.
The factors are erased immediately upon the gene becoming awake and active. It starts right back at 100% again.
We try to do our best to manipulate the genetics of a horse but because humans understand so LITTLE about genetics, the best thing we can do is simply - RIGOROUSLY test our stallions (who contribute the heaviest due to sheer numbers of foals sired by them, to the overall equine genome), strictly adhere to good conformational, athletic and temperament standards in our mare pool and provide the very best environment (feed, social interactions and lesson plans) to the foals.
That makes you think, doesnāt it? We breeders have a heavy responsibility. We can make or break our breed just by the very choices we make.
Thatās why the mantra of every responsible breeder is: Breed the best of the best mares to the elitest of the elite stallions.