This Saturday, the richest sprint on turf anywhere in the world, the $20 million Everest, is run at Royal Randwick. At the centre of it all is the defending champion: Ka Ying Rising.
He sits in rare air, the kind historically reserved for legends like Black Caviar and Dayjur. Timeform rates him 137, the same mark as Dayjur, the horse the British press called "the world's fastest" in 1990, and who lost the Breeders' Cup Sprint by a neck after jumping a shadow on the track in the final strides.
When you watch him unleash that effortless, explosive turn of foot, you think: "How can he be that good?"
As a self-confessed Pedigree Nerd, I had to try to find out why. Part of the answer lies in a single gene that scientists have nicknamed the Speed Gene.
Now, ask ten experts how to read a pedigree and you'll get ten different answers. What follows is simply my lens on Ka Ying Rising: the DNA science, the pedigree patterns, and what I think makes him tick.
What is the Speed Gene?
For centuries, breeders knew certain matings produced sprinters while others produced stayers. But nobody knew why until 2010, when a team led by Dr Emmeline Hill in Dublin found one of the key genes behind it.
Its proper name is myostatin. It controls how a horse's muscle develops: more of the explosive, fast-twitch type, or more of the economical endurance type.
It comes in two versions:
- C, the speed version
- T, the stamina version
Every foal gets one copy from its sire and one from its dam. That gives three possible "engines":
C/C: the Dragster. Two speed copies. Built for explosive pace, best from 1000m to 1600m.
C/T: the Hybrid Sports Car. One of each. Speed and staying power, best from 1400m to 2400m.
T/T: the Diesel. Two stamina copies. Built to grind, best at 2000m and beyond.
These are tendencies, not rules. But across thousands of horses, the pattern holds up.
Hidden for 250 years
Here's what most racing fans don't know: for most of thoroughbred history, the Speed Gene was practically invisible, and nobody wanted it.
That makes sense when you know how racing used to work. In the 1700s, races were often run over four miles (6,400m), sometimes in several heats on the same day, by mature horses. Stamina won. Breeders bred for stamina. Sprint speed was seen as a flaw, not a goal.
In 2012, Dr Hill's team went back into history to prove it. Working with Cambridge archaeo-geneticist Dr Mim Bower, they tested DNA from the skeletons of 12 legendary stallions foaled between 1764 and 1930, including the immortal Eclipse.
Every single one was T/T. Pure Diesels.
So where did the Speed Gene come from? The scientists traced it back to a single native British mare, about 300 years ago. Her speed version of the gene sat quietly in the breed for generations, until racing changed. Shorter races and two-year-old racing started rewarding horses that were quick and early. Suddenly, speed paid.
Who brought the Speed Gene into the modern spotlight?
According to the 2012 study, the modern spread of the Speed Gene traces back to a Canadian champion foaled in 1954: Nearctic.
Nearctic raced long before DNA testing existed, but his record tells you what kind of engine he had. A ferocious, free-running sprinter-miler, he won 21 of his 47 starts, was crowned Canada's Horse of the Year in 1958, and set six track records from 5 furlongs to a mile and a sixteenth.
When Nearctic sired Northern Dancer (foaled 1961), the Speed Gene found its way into an immortal stallion who became a global super-sire. Today Northern Dancer's blood flows through the vast majority of modern racehorses, usually appearing two, three, four or more times in a single pedigree.
And here's a fact Aussie racing fans will appreciate: the study found the Speed Gene is more common in Australia than almost anywhere else. Our love of early speed has been quietly selecting for it for decades.
The coin flips behind Ka Ying Rising
Sceptics look at a pedigree, see Nearctic six generations back, and say: "Too far back to matter."
But genes don't appear out of thin air. Every gene in Ka Ying Rising's body was inherited from an ancestor in his pedigree. So let's follow the trail down his sire line, his father, his father's father, and so on:
Ka Ying Rising ← Shamexpress ← O'Reilly ← Last Tycoon ← Try My Best ← Northern Dancer ← Nearctic
Every stallion in that chain could really run. Shamexpress won the Group 1 Newmarket Handicap over 1200m. Last Tycoon won the Breeders' Cup Mile. Try My Best won the Dewhurst as a two-year-old. Horses like that almost certainly carried at least one speed copy.
But here's the catch. A stallion with one C and one T passes on only one of them to each foal, at random. It's a coin flip. Heads, speed. Tails, stamina.
For Nearctic's own speed copy to travel all the way down that line to Ka Ying Rising, the coin had to land on heads six times in a row. The odds of the Speed Gene making that one journey:
½ × ½ × ½ × ½ × ½ × ½ = 1 in 64
To be clear, that's the odds of the Speed Gene arriving by that one road. (His overall chance of carrying the Speed Gene is much higher, because it can also come in through the dams along the way.) It's not the odds of breeding a Ka Ying Rising either. Those are far, far longer. The Speed Gene only gives a horse the right type of engine. To build a champion, you also need the right support from the dam's side, and you need to win the coin toss on plenty of other genes too. (More on those shortly.)
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Mum's double dose
Ka Ying Rising's mother is Missy Moo. She won 5 races from 28 starts. A good, genuine racemare, but not one you'd call elite.
Missy Moo's sire is Per Incanto, a son of Street Cry, the sire of Winx. And tucked inside Per Incanto's family is a familiar name: Try My Best.
Yes, the same Try My Best who sits in Ka Ying Rising's sire line.
So Try My Best appears twice in Ka Ying Rising's pedigree: once on his father's side, once on his mother's. His mother doubled up on one of the key speed sources behind his sire, giving Try My Best's genes two roads to reach him instead of one.
And it's not just any doubling up. Ka Ying Rising is linebred to Try My Best (in the 4th and 5th generations), and it's sex-balanced: one line comes through a son of Try My Best (Last Tycoon), the other through a daughter (Daffodil Fields). Why does that matter? Coming through both a son and a daughter gives the pedigree the chance to reunite both the male and the female genetic strains of Try My Best's bloodline in the one horse. That's a pattern I really like to see. New to linebreeding? Here's my plain-English guide.
The pedigree buffs among you will recognise this as a Tesio-style approach.
If plenty of horses have the Speed Gene, why is he so much faster?
Lots of racehorses carry the Speed Gene. Very few can run 1200m in 1:06.11, Ka Ying Rising's latest Sha Tin track record.
The Speed Gene tells you what kind of engine a horse has. It doesn't tell you how powerful it is.
My view is that Ka Ying Rising most likely has a Hybrid engine: the speed of a sprinter with the staying power to win at 1400m. But he's not a standard Hybrid engine. He's a Hybrid engine with modifications, and two of them stand out when I run his pedigree through my models.
He didn't just win one coin toss. He won them across generations, and across several traits at once.
The turbocharger: fast-twitch muscle power. A gene called MYLK2 is linked to how quickly and forcefully fast-twitch muscle fires. My model calculates a high likelihood that Ka Ying Rising inherited very favourable versions from his pedigree, and rates him at an elite level. If it's right, that means more horsepower, giving him that explosive, instant turn of foot the moment Zac Purton pushes the button.
The intercooler: clearing lactic acid. Every horse carries a gene called SLC16A1, which helps move lactic acid out of the muscles. My model rates as elite the likelihood he inherited the favourable versions of this as well. Think of it as an ultra-fast waste disposal unit, flushing lactic acid out of his muscles faster than an average sprinter. It may be part of how, in his 1:06.11 track record, he averaged just over 65 km/h for the full 1200m without getting heavy-legged.
Here's what caught my eye. When I ran Black Caviar's pedigree through the same models, she rated at the same elite level on both. Two of the greatest sprinters of the modern era, landing in the same rare spot on the same two measures. A word of caution: my models are still being tested, they work from a number of assumptions, and they calculate likelihoods from pedigree rather than testing DNA. Scientists are also still working out how much these genes matter in racehorses. But the numbers line up with everything we see on the track, so I think it's worth sharing.
Here's the bigger point. Racing ability isn't down to one gene. There are many, and every one of them is another coin toss at conception. The Speed Gene was one toss. Muscle power is another. Clearing lactic acid is another. Nobody can say for certain how Ka Ying Rising's coins landed. But if my models are on the right track, he didn't just win one coin toss. He won them across generations, and across several traits at once.
That kind of luck is rare. And it may be a big part of why horses like him come along only once in a generation.
There's more to this story
This story is mainly about the Speed Gene and its contribution to what makes Ka Ying Rising so special. There's a lot more going on in his pedigree, but we'll save that for another time.
Michael MarosaThe Pedigree Nerdmichael@digitalbloodstock.com
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Sources
- Hill EW et al. (2010). A sequence polymorphism in MSTN predicts sprinting ability and racing stamina in Thoroughbred horses. PLoS ONE.
- Bower MA et al. (2012). The genetic origin and history of speed in the Thoroughbred racehorse. Nature Communications.
- Race record, ratings and track records: Hong Kong Jockey Club; Timeform; ANZ Bloodstock News, September 2026.
- Nearctic's racing record: American Classic Pedigrees.
- Pedigree analysis and gene estimates: Digital Bloodstock models.