Northern Dancer--genetic freak?

[vineyridge]

I’ve been reading his biography by Avalyn Hunter, and the speed at which his lines came to dominate worldwide racing is pretty darned amazing.

And then I started thinking about what a short time it took for Impressive to dominate halter breeding in Quarter Horses. And then, if the Impressive mutation hadn’t had a fatal effect, wondering if it ever would have been discovered. And from that, wondering if perhaps Northern Dancer might have had a somewhat similar mutation that isn’t fatal and hasn’t been discovered yet. Because the one thing that Northern Dancer has done and is still doing is changing TB conformation toward downhill, short and compact, which has traditionally be described as QH. With the huge stallion books these days (Northern Dancer only serviced about 40 or so mares a year compared with up to 300 for modern stallions) and dominance in the mutation, it wouldn’t take very long at all to destroy the old type.

The cost of finding a mutation due to ND wouldn’t interest academic researchers most probably. I wonder if Grayson would find such a thing?

[Scribbler]

Why would this count as a mutation rather than just an inherent body conformation? As I understand it a mutation is when something new pops up. But downhill and short is just a type of horse. Perhaps you mean we should find a genetic marker for nd descendants?

[Spotless]

ND and Impressive were both born in the 1960s, so surely if ND had a genetic defect it would have been discovered by now. Being compact isn’t a genetic mutation (to a degree of course).

[vineyridge]

My thought was that since whatever made ND so prepotent didn’t rise to a “genetic defect” and cause fatalities, that it could well be a mutation no one went looking for. Genetic changes generally haven’t been looked for unless they have caused serious problems. Looking is a very expensive process.

[rubles]

Horses like Northern Dancer and Secretariat don’t come along very often and I’m glad they do. Scretariiat had a normally large heart–more ways than one. Northern Dancer–one of a kind and who knows for sure why. It would be nice to know why though.

[Scribbler]

@vineyridge

My thought was that since whatever made ND so prepotent didn’t rise to a “genetic defect” and cause fatalities, that it could well be a mutation no one went looking for. Genetic changes generally haven’t been looked for unless they have caused serious problems. Looking is a very expensive process.

I would imagine that one thing that could make a stallion prepotent is the amount of line breeding and inbreeding that occurs. That would concentrate both his genes and his phenotype. If mares were selected that shared his phenotype (low and compact) that would intensify the effect.

I’m not sure what mutation would cause a stud to be particularly prepotent. Isn’t it always a 50/50 chance which genes transfer from dam and sire?

I expect that as in human athletes there will be a range of physiological traits that we don’t necessarily test for in horses such as resting heart rate, ability of red blood cells, muscle twitch etc. Maybe an exceptional racing stud passes on an internal physiological advantage as well as a conformation advantage.

I don’t think that necessarily needs to be understood as a mutation though. It could just be a particularly advantageous alignment of the normal range of genes.

Like Michael Phelps having limber shoulders and really big feet. Great for a swimmer.

I wouldn’t be surprised if he was also born with greater than normal lung and heart capacity.

Definitely a genetic superstar. But not a genetic mutation.

There’s a difference.

If a swimmer was born with web feet like a duck that would be a genetic mutation that provided an advantage. Really big feet are just genetic luck.

[gumtree]

“Because the one thing that Northern Dancer has done and is still doing is changing TB conformation toward downhill, short and compact”

IMO this is casting a very wide blanket. Don’t have time to give my thoughts on the subject right now. But I did see a LOT of his get. and his sons, grandsons, great grandsons that went to stud along with their get. Lots of foals out Northern Dancer mares.

Me with Northern Dancer 1986 ish edited to add, I’m 6 foot tall
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[rubles]

OH lucky you. I could be envious!

[Gestalt]

You know I hear a lot of people talking about weedy tb’s,or downhill tb’s, etc. That is bad breeding. There are a lot of gorgeous, well boned, with good conformation tb’s. Four out of the four I’ve owned have been wonderful. And three out of the four were the soundest horses you’ll probably ever ride. One went lame by the time she was 12, but she was pasture sound. After bowing both front legs in race training before she was even two, her body didn’t have much of a chance. Picture 17h at two, that is not a baby you should push for speed.

[Texarkana]

So let me get this straight. A mutation through Northern Dancer is responsible for all downhill, compact, QH-like traits in thoroughbreds?

[vineyridge]

Of course it isn’t. But there IS a Northern Dancer conformation; he passed his on to multiple sons who passed it on to their offspring. I’m questioning if there was a genetic mutation that made him so very prepotent, precocious, and fast and made his sons also very prepotent in passing on their (his) talents and conformation. There WAS an Impressive conformation that he was able to pass on with great prepotency to his descendants. Why couldn’t the same be true of Northern Dancer but without the fatalities?

[vineyridge]

@Scribbler

I would imagine that one thing that could make a stallion prepotent is the amount of line breeding and inbreeding that occurs. That would concentrate both his genes and his phenotype. If mares were selected that shared his phenotype (low and compact) that would intensify the effect.

I’m not sure what mutation would cause a stud to be particularly prepotent. Isn’t it always a 50/50 chance which genes transfer from dam and sire?

I expect that as in human athletes there will be a range of physiological traits that we don’t necessarily test for in horses such as resting heart rate, ability of red blood cells, muscle twitch etc. Maybe an exceptional racing stud passes on an internal physiological advantage as well as a conformation advantage.

I don’t think that necessarily needs to be understood as a mutation though. It could just be a particularly advantageous alignment of the normal range of genes.

Like Michael Phelps having limber shoulders and really big feet. Great for a swimmer.

I wouldn’t be surprised if he was also born with greater than normal lung and heart capacity.

Definitely a genetic superstar. But not a genetic mutation.

There’s a difference.

If a swimmer was born with web feet like a duck that would be a genetic mutation that provided an advantage. Really big feet are just genetic luck.

Northern Dancer was notably neither inbred or heavily line bred. In his first five generations he has a double to Chaucer and one to Gainsborough in the fourth and fifth generations. There is quite a bit more duplication farther back, but that’s true of almost all TBs.

My Hypothesis would be that ND was born with a genetic mutation in something similar to Impressive’s that affected muscle development and was dominant. If that’s were the case then half of his foals would also inherit the beneficial and dominant gene, and pass it right on down to half of their descendants. If the myostatin C allele on Chromosome 18 can dramatically affect precociousness and tendency toward short or long distances, why couldn’t a mutation of that or something similar to that single gene that is also dominant explain the lasting success of Northern Dancer and his get? We do know that the presence of the C allele exploded with Neartic’s get.

Do we expect Michael Phelps to produce four or five generations of swimmers of his quality? If he does, then I might want to look for a genetic mutation.

[Elles]

https://www.google.nl/amp/s/www.pinterest.com/amp/colinnolte7/northern-dancer-legacy/
The mare that was recently sold at Tattersalls for 6 million has him three times in her pedigree and I do not think that mare has bad conformation.

[JB]

@vineyridge

Of course it isn’t. But there IS a Northern Dancer conformation; he passed his on to multiple sons who passed it on to their offspring. I’m questioning if there was a genetic mutation that made him so very prepotent, precocious, and fast and made his sons also very prepotent in passing on their (his) talents and conformation.

A single mutation would be highly unlikely to cause both precociousness and speed. I can see a mutation in, say, a hind leg ligament or tendon which might make it “snappier” and produce more rebound which could lead to some more speed, but even that would likely be a heterozygous trait, passed on 50% of the time. Then you’d have to end up with enough line breeding to produce a homozygous mare/stallion who then passed that on to all her kids. That would be really hard to track down.

There are a ton of stallions who are prepotent for passing on their style of conformation. Likely they have been homozygous for the desired traits, either by line breeding, or through careful breeding of like to like, so are more, or less always visible in the offspring

There WAS an Impressive conformation that he was able to pass on with great prepotency to his descendants.

It doesn’t quite work like that. Impressive was HYPP nH. 50% (ish) of his offspring were also nH (assuming he wasn’t ever bred to nH dtrs, I don’t know if he was).

Over time, there’s more and more line-breeding, so you get more and more HH horses, who then always produce ?H horses when bred

Impressive’s sought-after traits had less to do with actual conformation, and more to do with the highly sought-after muscle bulk of the Halter world. Then at some point everyone thought it was HYPP itself which caused the muscling, so HYPP actually became sought after, before anyone understood what it actually meant and STILL some people hang on to the notion that if they don’t have an HYPP horse, they can’t have that bulk, and we now know that is not true - there are (relatively) lean ?H horses, and there are bulky nn horses.

His actual conformation was probably more visible in his direct offspring, but there are so many Impressive-bred horses now, that even just 3 generations removed, the body types vary wildly, from ranch type to Halter bred. And I’m sure now there are even quite a few HUS and WP descendants, which would look nothing like him.

It doesn’t even have to be about a mutation. It could all just be the lottery of the right combination of the right dominant genes coming together in ND, which would then mean he had a much higher chance of passing on 1 or more of those, instead of just a 50/50 chance of producing speed, or precociousness, or staying power, or whatever.

[JB]

One reason why HYPP was “easy” to track down is there were symptoms that could be seen, and there became a pattern of management types that went along with those horses.

In racing, I would think that the variations in training, physical stressors leading to minute injuries, sheer desire, quality of farrier work, and more, would make it very difficult to even pinpoint which horses to, and not to do any testing on

[Scribbler]

@vineyridge

Northern Dancer was notably neither inbred or heavily line bred. In his first five generations he has a double to Chaucer and one to Gainsborough in the fourth and fifth generations. There is quite a bit more duplication farther back, but that’s true of almost all TBs.

My Hypothesis would be that ND was born with a genetic mutation in something similar to Impressive’s that affected muscle development and was dominant. If that’s were the case then half of his foals would also inherit the beneficial and dominant gene, and pass it right on down to half of their descendants. If the myostatin C allele on Chromosome 18 can dramatically affect precociousness and tendency toward short or long distances, why couldn’t a mutation of that or something similar to that single gene that is also dominant explain the lasting success of Northern Dancer and his get? We do know that the presence of the C allele exploded with Neartic’s get.

Do we expect Michael Phelps to produce four or five generations of swimmers of his quality? If he does, then I might want to look for a genetic mutation.

I meant that if there was a lot of line breeding in his descendants that would concentrate his genotype and phenotype.

I​​​​​f Michael Phelps got busy for the next decade with the international women’s swim teams from 5 continents and then all those love childten married their half siblings we might see some interesting outcomes. Maybe even web toes. But that’s not how it works with humans.

[RW-in-DC]

Can we write about prepotent sires and not mention the Morgan horse; a breed from one prepotent stallion in early American history? Won’t ND have a ways to go to be as storied as that horse?

[Joanne]

@Elles

https://www.google.nl/amp/s/www.pint…dancer-legacy/
The mare that was recently sold at Tattersalls for 6 million has him three times in her pedigree and I do not think that mare has bad conformation.

Marsha. 6 million guineas. It was $8,469,783 US dollars.

http://www.thoroughbreddailynews.com…ropean-record/

[snowrider]

@JB

A single mutation would be highly unlikely to cause both precociousness and speed. I can see a mutation in, say, a hind leg ligament or tendon which might make it “snappier” and produce more rebound which could lead to some more speed, but even that would likely be a heterozygous trait, passed on 50% of the time. Then you’d have to end up with enough line breeding to produce a homozygous mare/stallion who then passed that on to all her kids. That would be really hard to track down.

That’s not really how genetics works. Downhill vs uphill confirmation is actually quite a huge difference in an animals physiology, you don’t see such differences in wild populations- half of all antelopes are not built uphill vs downhill. And it’s been consistently bred in and out of various breeds throughout history for pulling vs running vs pleasure riding. However most breeds which consistently produce either horses with a very high or low headset are fairly tightly genetically restricted or were at one point with mixed populations producing more unpredictable offspring So it seems to be a malleable yet not terribly predictable trait in horses, which could mean it’s tied to the expression of a small number of genes: neck angle,shoulder slope throat latch, gaskin length- all related but separate OR it could mean that there is a developmental cascade that means that if one trait develops a certain way then others must follow so really it is tied to a few genes or one main one- although unlikely (these are basic and not very technically correct explanation).

the Impressive mutation is an example of one change that causes others in response to the greater muscle mass etc.

And yes I know that headset and “uphill confirmation” are not exactly the same thing but they are darn close.

[JB]

@snowrider

That’s not really how genetics works. Downhill vs uphill confirmation is actually quite a huge difference in an animals physiology, you don’t see such differences in wild populations- half of all antelopes are not built uphill vs downhill. And it’s been consistently bred in and out of various breeds throughout history for pulling vs running vs pleasure riding. However most breeds which consistently produce either horses with a very high or low headset are fairly tightly genetically restricted or were at one point with mixed populations producing more unpredictable offspring So it seems to be a malleable yet not terribly predictable trait in horses, which could mean it’s tied to the expression of a small number of genes: neck angle,shoulder slope throat latch, gaskin length- all related but separate OR it could mean that there is a developmental cascade that means that if one trait develops a certain way then others must follow so really it is tied to a few genes or one main one- although unlikely (these are basic and not very technically correct explanation).

Well, of course. The original comment I was replying to was someone wondering

“if there was a genetic mutation that made him so very prepotent, precocious, and fast and made his sons also very prepotent in passing on their (his) talents and conformation.”

The answer is no - it isn’t likely there’s any single mutation that caused that combination, and I offered up just one potential mutation that might be a trait that might contribute to, in the example, speed.

the Impressive mutation is an example of one change that causes others in response to the greater muscle mass etc.

Not entirely sure I follow that lol

HYPP is thought to make some horses more muscular as a result of muscle fibers chronically contracting/relaxing, so they are in a constant low-grade state of “body building”, in response to a defective coping mechanism with regards to potassium channels. It’s not anything that happens “in response to the greater muscle mass”. The greater muscle mass IS the response in some cases, and is simply a tag-along in others… There are non-HYPP horses who are beefy, and there are HYPP horses who are not.

And yes I know that headset and “uphill confirmation” are not exactly the same thing but they are darn close.

Not as close as you’d think. Yes, too low a neck set does greatly detract from being functionally uphill. But there is also where the front legs are in relation to the withers, and where the LS gap is in relation to the point of the hip.

A horse can have a higher neck placement, have a poor pillar of support, and a poor LS gap, and have no athletic ability to sit behind or elevate in front.

Or he can have a lower than ideal neck placement, excellent PoS and excellent LS gap, and be very uphill in movement.