Breeding Theory

[Argent]

A few links from a site I find very informative.

Breeding Principles
The Mare
Pedigree Study
Pedigree Generation Position
Potency Primer
Siblings
Understanding Pedigrees

I don't know that any of these concepts can be added into a game, but I find them interesting to read about.

I've also been reading about COI and its questionable value as applied to breeding. The idea is that the calculated value isn't a reliable indicator of homogeneity of genes in a particular horse; the value could be higher or lower - marginally or substantially -- and therefore the entire concept is of debatable worth. With this in mind, I would hope that horses would not be punished or rewarded for their calculated COI. Maybe the game itself could have a hidden, true COI to base rewards/penalties on?

EDIT: I'm also curious if there will be true "superior" bloodlines within HWO -- sires and dams that are truly exceptional and unique -- or will it be possible for any horse of any breeding to be elite?

[larissar]

I'm very interested to read these links tonight. Thanks for sharing.

Yes there are planned some elements which are calculated based on the COI to an extent. If you know of another method of calculating a "true" COI I'm open to suggestions.

I can't find the link right now for the site that explains the method I used, but I believe it's a fairly common method, and likely the one you mention as potentially being inaccurate.

[larissar]

I'm designing the game so that there will be superior bloodlines, it will likely take a number of generations before these lines emerge from within a gene pool. But only real game play testing will tell this for sure. I'm hoping we can determine if this is the case during Beta Testing when more users join the group.

[Argent]

If there were actual hidden detrimental genes, I could see those as being a viable, honest way of determining which horses should be penalized; in that case, it wouldn't be inbreeding itself that was punished, but inbreeding to unsound horses, which I think is perfectly fair. As is, my faith in COI is shaken, though I still think it is valuable to see just how related the parents of a particular horse are.

Another potentially useful feature would be Ancestor Loss Coefficient (AVK), which calculates how many unique ancestors there are in relation to the total number of potential ancestors. The same number of generations used for COI are used for a corresponding AVK. NIfty online tool I've been fiddling with for a while.

Excellent; I'm really excited to hear that.

[larissar]

If there were actual hidden detrimental genes, I could see those as being a viable, honest way of determining which horses should be penalized; in that case, it wouldn't be inbreeding itself that was punished, but inbreeding to unsound horses, which I think is perfectly fair.

This -exactly- is my plan. Good genes and bad genes.

I'll look into that AVK too and see what I can add in

[Argent]

This -exactly- is my plan. Good genes and bad genes.

We need a like button

[larissar]

Agreed!
I've just spent a half hour reading through those links you posted, and now I'm even more excited to try out my own game lol. I've got to get competitions and training finished to we can really give this a good go!

If you happen to know of any articles discussing specifically which sex-linked attributes are found in fillies and colts then I can apply that to the game as well so that sex-balancing of pedigrees can be a -thing- in HWO too. If no articles are found I do have some ideas on how I can implement this myself, but real science is always better.

Edit: because of this thread I've added colour-coding highlighting of duplicate individuals within a pedigree. It doesn't look very nice right now, but it's functional.

[Argent]

The only sex-linked attribute I've heard of thus far is the large heart gene, which is on the X-chromosome, but I'll look for others
I'm not sure what exactly is the dynamic behind the sex balanced pedigree; the articles didn't seem to provide any scientific basis for it, just anecdotal -- though well supported -- evidence.

[larissar]

Yeah I've known about the Large Heart gene before. It does make complete sense though, there must be many more sex-linked genes at play, on both X and Y. Focusing on only side of the story, the sire as so many have done in years past, can cut out those female linked genes. Genetics is so fascinating to me!

[Argent]

According to this article, sex-linked genes only appear on the X chromosome. In general, the consensus seems to be the the Y chromosome itself doesn't code for much beyond not-female.

EDIT: Apparently, there is a "speed gene" in TBs.