Will mankind ever stop evolving?

To answer this question, we turn to horses. Why? Until recently, scientists thought they had reached a genetic limit when it came to speed
05 January 2016

Interview with 

Dr Jim Usherwood, the Royal Veterinary College


Will there ever be a point when we stop evolving? There might be a clue when Different horseswe look at horses. For years, scientists thought that race horses had reached their selection limit. They'd been bred and bred - the faster stud paired with the fastest mair - but trainers just couldn't make them any faster... However, some research published recently suggests that this may not be the case, as Jim Usherwood explained to Graihagh Jackson...

Jim - Okay, so we've been measuring race horse times for hundreds of years and over the last couple of decades, the very best horses have really been doing the same sort of times for the same sorts of distances and, we've been thinking of that, really they're not getting much better despite all the efforts in breeding and training that have been put in.

Graihagh - That's Dr Jim Usherwood from the Royal Veterinary College. There is a caveat here though. For thoroughbreds, there isn't a big enough gene pool or, you might say, not enough top dogs to mate with...

Jim - Here we're talking about thoroughbred racehorses and this is thoroughbred with a capital T which declares the breed, and the rules for being allowed to race in these races are fairly strict and constrain your breeding really quite strongly.

Graihagh - However, a publication earlier this year suggested that actually, we may have had it all wrong...

Jim - So there's this interesting, fairly recent study that shows that in elite short distances races, time is getting a bit better.  They agree that the winners of the elite races at medium/long distances aren't changing much but, in the shorter distances, they do appear to be getting better.

Graihagh - Why might this be the case?  Why might they be stopping short at the mid to long distances but getting faster at the short distances?

Jim - The authors of the Exeter report suggest that there could be a new influx of genes coming in from America.  Where I say new, they're still all thoroughbreds but, no, it can't be apparent from that kind of measurement whether it is genes or training.  Both could have accounted for a change there.

Graihagh - So horses haven't appeared, at least, to have reached their selection limit.  Do you think we'll ever get to a point where they will?

Jim - So, you can't infer from times whether it's selection limits or whether training is changing, of course.  Do I think that they might reach some genetic limit?  I just feel as though the limited genetic pool will probably constrain things to a certain extent.

Graihagh - Obviously with horses, we're choosing which horses to breed with which but, I suppose, when you're taking into account humans, that's a very different matter.  Would you ever consider humans to reach, perhaps, a selection limit?

Jim - When you're thinking about humans, of course, the genetic diversity is huge.  We don't have a Jockey Club or a Greyhound Board saying 'only these sorts of humans can race,' so we do have some diversity to work with.

Graihagh - Because there's so many of us and we're intermingling with each other all the time - there are a huge number of genes floating around - unlike the world of thoroughbred horses. But is there a limit on what we could achieve? Will we just continue to run the 100m faster and faster or will we just level off?

Jim - I think every time boldly write down what this limit is, the fun of athletics is that we tend to be wrong, and demonstrably so.  Before Usain Bolt, we are not saying those times are going to be broken.  Put it this way something as fundamental as why you get tired when we run isn't terribly well understood.  We can observe that we do, but why do we get so much more tired running than cycling?  And if you can't do something as simple as that then I doubt any guess at what estimates of top speed.

Graihagh - One thing that springs to my mind is - I'm thinking of all the sorts of drugs but also all the technical advances in say shoes or what have you - surely we'll just engineer stuff to meet our needs, to make us faster?

Jim - So that's one of the odd things about sport.  They go about putting some pretty arbitrary constraints on what you're allowed to change.  You could say shoes - you should be getting faster and faster shoes.  Yes, faster shoes have been invented, and then banned.  You can think of brush spikes, or you can think the Fosbury flop was allowed but somersaulting long jump isn't allowed.  So it depends on what the sports going to allow as to how much you're going to allow technology or technique to radically change things.

Graihagh - Would a simple solution just not to be 'hey, let's just have two different Olympic races.'  Let's have one with all the technology we can possibly get to see how fast we can get versus a more standard approach, I suppose what we do today.

Jim - And there you're touching on the ideas that motorsports got.  Do we allow technology to be part of the sport?  And sport doesn't have a consistent answer to that.  Cycling is an interesting one where the Tour de France put constraints on bike design to keep it fairly even, keep if fairly consistent across the years.  The Tour de France bikes are by no means the bicycles that we could design but it's losing some of the fun of the change you could make.  I'm torn between the two.  Should it just be a pure measurement of what humans can do - maybe...  I do quite technology actually.

Graihagh - I think in my eyes I think I'd quite like to change to see just what we could achieve if we were allowed to.

Jim - Are you interested in how humans can change? In our muscles and biomechanics can change, or are you interested in how well you can make a pole vaulting pole?  Of course, a better pole vaulting pole allows you to jump higher.  At some point, you don't want one that pings somebody so high that they get really, really hurt.  You could imagine weird prosthetics that would allow you to run really fast, but it means that you could really hurt yourself if you go round the corner the wrong way.  So there are bits where you want to keep people safe and you've got the question of - do you want to measure technology or humans?  Athletics tends to be focused on the humans.


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