Northern Dancer--genetic freak?

[snowrider]

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.
They can but that’s uncommon and usually something you see in cross breeding horses with different body types. Most populations are one or the other.

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.

You have no basis for that statement though. It is fairly well understood that both speed and build are heritable and that a downhill confirmation is associated with speed on the flat in short races. It is heritable. You claim that it is definitively not tied to one gene but you don’t know that and I don’t. No one does. Clearly things affect speed and athletic performance other than confirmation like cardio vascular issues and tissue healing, slow vs fast twitch muscles etc. But for the small set of US bred dirt track, short race o rented horses we don’t know if downhill build is associated with one bloodline and with speed. It’s an interesting question as two of the main things driving breeding in modern horses are speed and an uphill movement.

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.

HYPP causes horses who shouldn’t be beefy to be beefy though, that’s the downstream effect of the single gene mutation. You may see a dramatic increase in visible muscle mass in descendants, and an increase in things like bone density etc in response but it’s pathological.

[JB]

@snowrider

They can but that’s uncommon and usually something you see in cross breeding horses with different body types. Most populations are one or the other.

There are plenty of,for example, Paints and QHs, with 1 or 2 of those things in pretty good shape, and 1-2 of them fairly poor. It’s not that uncommon in breeds with no breeding approval process.

You have no basis for that statement though. It is fairly well understood that both speed and build are heritable

I never said they aren’t heritable, as clearly they are. My comment was that it’s highly unlikeiy it’s a single mutation/gene responsible for it. Speed is a function of many different body part working together in the right way, so many different genes that affect not just conformation (to include length and angles of all the bones in the hind end), but whether a horse has more fast or slow twitch muscles.

and that a downhill confirmation is associated with speed on the flat in short races. It is heritable.

Of course it is.

You claim that it is definitively not tied to one gene but you don’t know that and I don’t. No one does.

I never said definitively, I said it’s highly unlikely

Clearly things affect speed and athletic performance other than confirmation like cardio vascular issues and tissue healing, slow vs fast twitch muscles etc.

Exactly and there is no single gene for all those things

But for the small set of US bred dirt track, short race o rented horses we don’t know if downhill build is associated with one bloodline and with speed.

Downhill builds exist in the horse, period. I assume you are talking about butt-high, because there is a huge difference between a butt-high horse, and a horse who is functionally downhill. Speed is difficult for a the functionally downhill horse, but not necessarily difficult for the butt-high horse, depending on other factors. But given that conformation traits are indeed heritable, there are certainly lines who are more or less butt-high, and if that is a factor in helping with speed it will continue to be bred for.

HYPP causes horses who shouldn’t be beefy to be beefy though, that’s the downstream effect of the single gene mutation. You may see a dramatic increase in visible muscle mass in descendants, and an increase in things like bone density etc in response but it’s pathological.

how do we know they shouldn’t be beefy? There are enough beefy nn horses and enough lean ?H horses, to know that it’s not a 1:1 correlation.

[btswass]

Now I know nothing about breeding but my thoroughbred who was bred to race but never did has northern dancer in his pedigree 3 times and is the exact opposite of short and compact

[halt]

@btswass

Now I know nothing about breeding but my thoroughbred who was bred to race but never did has northern dancer in his pedigree 3 times and is the exact opposite of short and compact

That’s because several of ND’s more prolific sons tended to be very long and rangy. I’d hardly call him a stallion that makes short and compact.

[ladyj79]

In case I missed it, as a breed, quarter horses did not exist until the 1940s. What they were was primarily thoroughbreds, with a few other things added in (Morgan/spanish) and then purpose bred for particular disciplines based on phenotype. And to this day, thoroughbreds are injected regularly. So rather than say tbs have come to be like quarter horses, it’s better to know that quarter horses were tbs, continue to be infused with tb and no other blood, thus as tb breeding and phenotype shifts, so too do quarter horses.

[Pronzini]

When someone implies that Northern Dancer sired only short and compact, I think about Nijinsky and Sadlers Wells. Northern Dancer sons didn’t all look like Danzig.

[vineyridge]

According to Deb Bennett, Northern Dancer’s compact conformation, passed on to horses like Storm Cat, is the result of centuries of Eclipse on top.

[Texarkana]

@vineyridge

According to Deb Bennett, Northern Dancer’s compact conformation, passed on to horses like Storm Cat, is the result of centuries of Eclipse on top.

Pretty much every prominent sire line in the US has Eclipse on top. Seems like a stretch to claim Eclipse is to “blame” when you’d be hard pressed to find a horse without him in spades.

[vineyridge]

Not only does every prominent sireline pretty much worldwide have Eclipse on top, but it is the Eclipse line from Waxy/Whalebone that has the mutation in the Y Chromosome that is found only in that line. Herod and Matchem have the classic Y that is found in almost all riding horses that do not have a TB sire line from Waxy/Whalebone. St. Simon didn’t have it, and that proves Eclipse didn’t have it.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3616054/ is a fascinating article about the Y Chromosome in modern horses.

One could argue that there was something about the Waxy/Whalebone Eclipse line’s Y mutation that has made that line of TBs so dominant in sires. And if a random mutation can occur in the Y, a random mutation can occur anywhere else; and if it provides a benefit, people will breed for it.

Dr. Deb Bennett was pretty adamant about the “Eclipse” conformation, but it could well be the Waxy/Whalebone one. I believe she is a recognized conformation guru.

[Elles]

http://www.pedigreequery.com/footpad8

[Elles]

http://www.pedigreequery.com/old+guard4

[mscapen]

I have a ND bred mare not close or repetitve but as for conformation very much compact a bit downward low set short neck huge swingning canter the only thing not ND in her body is the face which is a very much SS face.
Not very athletic but has no quit and will think things through. Loves to jump and will figure stuff out for herself. If left to her own devise she will only canter left, request the right and you can see the wheels turn in her brain and she will do a light skip lifting her shoulder very interesting to watch less easy to sit to.
Here she is ( pic taken by non pro in the spring while shedding out: she only support the deep mohagy baie in the winter, summer coat is sort of caramel) :
http://www.pedigreequery.com/epic+song

[Janet]

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.

Do you mean the “large heart” gene on the X chromosome?

[Elles]

Fifth today in the Cheltenham Gold Cup.
http://www.pedigreequery.com/djakadam

https://www.google.nl/search?q=djakadam&dcr=0&prmd=nisv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiJ_OOpoPHZAhURZVAKHbhHAA4Q_AUICigC

[Elles]

The other two horses I posted the pedigrees of are also steeplechasers.

[vineyridge]

Native River, the winner of the Gold Cup, has “only” eight lines to Nearco and only one to Northern Dancer.