Raise A Native Sire Line

[DDT]

Stan

Runners from the Mr. Prospector line and expanded to Raise a Native make up a sizable portion of each crop, many more chances to be one of the 20 starters in the Derby. Almost one third of the top 150 sires by progeny earnings are sons, grandsons and great grandsons of Mr. Prospector which gives me the indication that not only are there a lot of runners from this line, there are also more than their fare share of stakes winners. Add to that the fact that many of these stallions are booked to the best mares giving them another advantage at siring a superior runner. As to his daughters, they may not have produced many Classic runners, but they kept Mr. Prospector at the top of the Broodmare's list for many years. If Mr. Prospector had 500 daughters in production each year, the chance that one or two of them would produce a classic runner are pretty slim. It would be wise to keep in mind the fact that we are talking about three specific races restricted by age, each crop has one chance to run in the Derby, Preakness and Belmont.

DDT

[Pan Zareta]

pan zareta

If the y has no performance genes, then how can one explain the big difference between the Ran sire line being so successful in all 3 legs of the triple crown and the Ran broodmare sideline being so unsuccessful in these three jewels of the triple crown?

Perhaps certain genes on other chromosomes can only manifest themselves in the presence of the Y chromosome.

Hypothetically, genetic 'imprinting' is one genetic factor that could be influencing those statistics. Certain genes are 'switched on' and expressed only if rec'd. from the male parent, others only if rec'd. from the female parent. Undoubtedly, the various environmental factors mentioned by other posters also have to be factored into the equation.

[aethervox]

I would like to point out that, in mammals, some genes are only expressed if inherited from the father.

As an example, according to this paper (http://hmg.oxfordjournals.org/content/7 ... 9.full.pdf) in sheep "The callipyge gene phenotype (‘beautiful buttocks’) is only expressed when paternally inherited."

That could explain why some 'sire lines' seem to dominate.

Just a thought...

[Bast]

As an example, according to this paper (http://hmg.oxfordjournals.org/content/7 ... 9.full.pdf) in sheep "The callipyge gene phenotype (‘beautiful buttocks’) is only expressed when paternally inherited."

Am I correct to assume that you are talking about traits that are expressed only when paternally inherited but may still be inherited without expression from the dam?

That would mean a sire could have success due in some measure to a mare somewhere in the pedigree of his sire...

[xfactor fan]

stancaris,

One of the reasons that the RAN sireline has produced so many more winners than daughters, is the huge disparity in numbers.

Lets say the average mare can produce 10 foals in her reproductive lifetime, a stallion many times that number.

You'd have to look at the total number of RAN sire line foals, and then figure out what percentage meets your criteria for success. Then do the same for the daughters. Then look at what the numbers are telling you.

As for the sheep and parentaly expressed genes, it isn't as simple as following the male line of descent. Took the Australian researchers many years to work out the genetics of this gene.

[Pan Zareta]

That would mean a sire could have success due in some measure to a mare somewhere in the pedigree of his sire...

Yes. Autosomal genes are present in double copy, one from each parent. With paternally imprinted genes a horse expresses only the copy received from his sire (~50% chance that came from the paternal first dam), but can and will transmit either that copy or his (unexpressed) own dam's copy to his progeny. Whichever copy his progeny receive from him is the one they'll express. Their dam's copy will be deactivated but, again, transmittable. Works the same way with maternally imprinted genes.

[aethervox]

Since the first detailed equine Y chromosome gene map was constructed in 2011, I think it's a little early to say whether or not there are genes on the Y chromosome that may affect a horse's race performance in some way.

Mammal Y chromosomes do vary from species to species, so what is true in humans may not be true in horses.

I prefer to keep an open mind and be open to theories, until they are proven wrong.

After all, the theory of plate tectonics was once considered crazy.

[DDT]

aethervox

If Zenyatta does not prove that the Y chromosome is not necessary in the genetic makeup of a superior runner then I do not know what would. In addition, she also goes against the time honored tradition that fillies are physically smaller than colts and should have their own division of racing. If a stallion only produced superior sons then that would tend to prove that the Y is something special, however, in the real world it is not that way. To date, no performance genes have been found to be located on the Y. I have the opinion that none will be found.

DDT

[Pan Zareta]

Since the first detailed equine Y chromosome gene map was constructed in 2011, I think it's a little early to say whether or not there are genes on the Y chromosome that may affect a horse's race performance in some way.

Mammal Y chromosomes do vary from species to species, so what is true in humans may not be true in horses.

I prefer to keep an open mind and be open to theories, until they are proven wrong.

After all, the theory of plate tectonics was once considered crazy.

A detailed map of the equine Y chromosome has been available since Santani's dissertation, 2004. Mapping is not a pre-requisite to exloring the level of diversity in the equine Y. So far that level is zero. In that case the only advantage for race performance anything on the Y might offer is a male v. female bias. We already know such exists, on average, not to ignore past, present and undoubtedly future exceptional fillies & mares.

[aethervox]

If Zenyatta does not prove that the Y chromosome is not necessary in the genetic makeup of a superior runner then I do not know what would. In addition, she also goes against the time honored tradition that fillies are physically smaller than colts and should have their own division of racing. If a stallion only produced superior sons then that would tend to prove that the Y is something special, however, in the real world it is not that way. To date, no performance genes have been found to be located on the Y. I have the opinion that none will be found.

Please don't put words in my mouth. I'm not saying that the Y chromosome is necessary in the genetic makeup of a superior runner. What I said was:

I think it's a little early to say whether or not there are genes on the Y chromosome that may affect a horse's race performance in some way.

I know that there have been superior fillies and mares. I'm just pointing out that science doesn't know everything yet.

In that case the only advantage for race performance anything on the Y might offer is a male v. female bias. We already know such exists, on average, not to ignore past, present and undoubtedly future exceptional fillies & mares.

Precisely. As a What If scenario: suppose that the RAN Y chromosome had a mutation that caused slightly higher testosterone levels?

Nature is not a machine and there are many variables that can affect performance, including male hormones.

Just my opinion.

[DDT]

aethervox

I did not quote you and I surely do not want to put words in your mouth. You have the opinion that the Y may contain performance genes or control hormones that go to performance. I have the opinion that the Y determines sex and little else.


DDT

[stancaris]

Let's assume that you guys are correct and that the Y chromosome in the horse carries no performance genes whatsoever.

Back in 1968 there was a woman Russian runner who was competing in the Olympic events and who was found to have Y chromosomes in some of her cells. She was in essence a mosaic where some of her cells were the XX type (female) and others carried the XY (male). She was beating all the girl runners and was disqualified from competing against the girls in the Olympics that year. The Olympic committee said she could only compete against males and not woman because she wasn't truly a woman (having XY cells in her body). I think she gave up and didn't compete from that time on.

Main Point: If the y chromosome made her faster than her female competitors then one cannot dismiss the Y chromosome as being insignificant.

In addition, Pan Zareta pointed out that imprinting may also occur with the presence of the Y chromosome making other genes on other chromosomes manifest themselves and perhaps this may at least in some way account for the dominance of the RAN sire line in all three legs of the Triple Crown. Whether it be the Y chromosome or the Y chromosome in conjunction with other chromosomes---The RAN sire line reigns supreme in the Triple Crown events. Perhaps a sire line is really more than just the mere inheritance of the Y chromosome. Certain genes may only go to work to produce their effects in the presence of the Y chromosome and the hormones it produces.

[Pan Zareta]

What If scenario: suppose that the RAN Y chromosome had a mutation that caused slightly higher testosterone levels?

If so, don't you think evidence for same from routine stallion fertility checks would have accumulated and become a matter of public awareness? Granted, the Y chromosome is not immune from mutations. A mutation on the Y could have been responsible for the reduced (in some cases nonexistent) fertility of St. Germans' descendants in 'tail male'. 'Never say never', but one or more TB males have been included in at least 3 of the published studies to date, none of which found any functional variability on the Y, and at least one of which tested 30+ breeds/types.

[aethervox]

Hard data on the Raise a Native (RAN) sire line in the Belmont.

1993 was the last year where none of the entrants had RAN tail-male.

From 1994 through 2011 (18 years)

Colt sire line:
Darley Arabian, no RAN - 111 entries, 3 winners
Darley Arabian with RAN tail male - 60 entries, 13 winners
Godolphin Arabian/Barb - 5 entries, 1 winner.
Byerley Turk - 1 entry, 0 winners.

Fillies - 4 entries, 1 winner.

From my preliminary data it looks like horses that are tail-male to RAN do win at a higher percentage than would be expected from the number of entries.

[DDT]

Other entries out number RAN 2 to 1 in that time span, and I am not saying that the Mr. Prospector connection to these runners and winners is not due to his influence. What I am saying is the Y is not responsible for it. Again, we are talking about 3 races, the majority of the 60 RAN entries in the Belmonts won stakes races before and after the classics. The Mr. Prospector sire line is well represented on any list of leading sires. This translates to good mares being bred to these stallions. That translates into runners bred and aimed for the classics.

DDT