Genes Behind the Scenes

[loboLoco]

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Video link:

This week, pups are being born across Yellowstone and beyond. Pups look fairly similar at birth but each one will grow a coat based on its parent’s genetic profile. So let’s take a look at the genetics that determine coat color.

We’ve always had a simple genetics model in the game for puppy coats, but we’re making a much more accurate model now for WolfQuest 3. Genetics has always been a bit daunting for me, but fortunately my neighbor Nathan is a geneticist, and after he explained it to me three times, I think I finally got it.

Most of the wolf’s genome has not yet been analyzed, but in 2009, scientists discovered a gene variant that controls coat color. This got a lot of press at the time because they found that it comes from dogs, many thousands of years ago, meaning that wolves and dogs have cross-bred in the past. They named this gene variant the “k locus.” Every wolf has two copies of this gene which, using standard genetics terminology, is indicated by a small “k” for gray coats or a capital “K” for black coats.

Other genes presumably affect the lightness or darkness of the coat, as well as the gray/brown tint, but these have not been discovered yet. (Genetics is expensive and there’s not a big financial payoff for sequencing the wolf genome.) Keep in mind “white” is tint of gray and is not caused by albinism. Because there have been no known albino wolves in Yellowstone there will be none in WolfQuest (we get a lot of requests for albino wolves).

So the K locus determines the wolf’s coat color:

* If a wolf has two small k variants (e.g. kk), then it has a gray coat (which might be anything from white to dark gray or brown).
* If a wolf has one small k and one big K (Kk), then it has a black coat (since K is dominant). This combination appears to give wolves extra resistance to disease.
* If a wolf has two big Ks (KK), then it is black…but it’s probably also dead, since this combination is usually fatal before birth.  

Based on this, we can accurately determine whether a pup will have a black or gray coat, based on its parents’s genes. The Punnett Square is a helpful diagram for figuring this out:

If both parents are kk (both have gray coats), then all their pups will have gray coats:

Punnett Square with kk parents

punnett square -kk-kk-s.png (339.7 KiB) Viewed 8058 times

If one parent has a gray coat (kk), and the other has a black coat (Kk because KK rarely survive), then each pup has a 50% chance of being Kk (black coat) and 50% chance of gray coat (kk):

Punnett Square with Kk and kk parents

punnett square Kk-kk-s.png (325.57 KiB) Viewed 8058 times

If both parents are black and Kk (because KK wolves rarely survive), then each pup has a 25% chance of being KK (black, and probably dying in utero), a 50% chance of being Kk (black), and a 25% chance of being kk (gray):

Punnett Square wtih Kk parents

punnett square - Kk-Kk-s.png (318.16 KiB) Viewed 8058 times

How will this work in the game? We will generate a genetic profile for each wolf which includes the K locus for coat color as well as other genes for coat tint and stats. For the player, this will be based on the wolf’s customization configuration (you choose and then the game generates the genetic profile). For NPC wolves, it’ll be generated dynamically for each wolf, based on Yellowstone’s wolf population (for an accurate distribution of gray and black coats) and standard genetics probablistic rules. So when your wolf meets a potential mate, you can infer a bit about its genetics and decide if you think it’s a good match:

* If you have a gray coat (kk), then choosing a black wolf (which is probably Kk) gives your pups at least a 50% chance to be Kk, and thus have higher disease resistance.
* If you have a black coat (probably Kk, but small chance of KK), choosing another black wolf could give your pups higher disease resistance — but there’s a good chance (25% to 100%) that some pups will die before birth. Litter size in WQ3 will vary (probably between 4 and 7, but we’ll tune that during beta testing), and this risk of a KK pup will add another element of uncertainty to litter size.

It’s very exciting to have this knowledge about the risks and rewards of the K locus so we can model those in the game. We also will include coat tint and stats in the genetics profile, but since scientists haven’t sequenced the genes that control those traits, we’ll use them only to determine those traits on the pup, without any health effects.

And thanks to Neamara for the adorable wolf faces!

Read more about wolf genetics in these articles:

Biologists solve mystery of black wolves
http://newsroom.ucla.edu/releases/biolo ... bout-80301

Heterozygote Advantage in a Finite Population: Black Color in Wolves
https://academic.oup.com/jhered/article ... 57/2961897

[Wolvencall]

Finally!!!! I'm currently taking a genetics and evolution class and this is what I've dreamed if I this game dihybrid crosses are so much fun as well if you wanted to delve further into it. I'm so excited!!!! With the KK pups it seems to be a lethal dosage effect just like with manx cats if they have a homozygous Gene for no tail most of their spine won't form and the fetus will be naturally aborted in the womb as it's inviable. But if it's heterozygous the kit will survive

Also I love that it's not an outrageous number of pups because there is a trade off with parents and offspring. Female wolves will want to produce quality eggs but there's a trade off between quality and quantity so a decision has to be made especially with larger litters and siblicide. That's why you typically only see one female reproducting because typically the average pack cannot support two litters of pups averaging out to be 10 pups. It's almost impossible because most pups will either be hungry with stunted growth if you try to save them all or if you can't provide enough food or some will die and the others will flourish and grow to normal size once there is less competition for food. There's an important trade off in that quality versus quantity as to why some females will reject their own pups if the litter is too big

[PearlyReborn]

First of all: THE PUPS AT THE END WERE SO PRECIOUS

But seriously, more realistic genetics will make finding a mate an interesting choice! I cannot wait! Anticipation is high!

[Gillato]

DUDE YESSS!!! THIE IS SOOO AWESOME AND THE PUP"S OMGOSSSH THEY LOOK LIKE LIL JELLYBEANS!!!! SWEEEE THERE SO CUTE CREDIT TO THE ANIMATOR!

[Black Burn]

Those puppies are sooooo cute!!! And the little heads are adorable too, good job Neam! So my wolf would be a Kk, it's interesting learning about coat genetics and what effects they have!

Seven pups.. That's a lot of mouths to feed! It will certainly be a great challenge!

Those pups at the end were the most adorable thing I've ever seen!! I can't wait to play with them!!

Keep going WolfQuest Team! You always have my full loyalty! And thank you for putting so much work into this!!!

[duskypack]

At this point I want to giggle a little because ultimately my favorite game is also becoming my dream game. You add things I don’t even think of! The educational aspects of this game are increasing in a million different ways and I hope that you guys receive lots of publicity for this unique labor of love that you’re doing.

[Phasoli]

I absolutely love the research and realism that is being put into the game! Choosing a mate and having pups is going to be a whole new educational experience. Wow! And the puppies at the end... oh my, they've stolen my heart! <3

[Sambhur]

ohh i love it when genetics make their way into things. with each developer post my excitement grows!

[Polynesia]

I love games that have genetics in them! I have a suggestion that there could be a small chance for a puppy to inherit his colour from an ancestor. It would be a cute surprise if my mate and I are both white, and one of our puppies inherits a black coat.

I also understand that new coat colours are not your priority until after Tower Fall, but I just wanted to ask if you would be open to considering a white wolf, like White Lady of Yellowstone? The current one is a beautiful coat, but it has never looked much like a white wolf to me. (It looks more like a wolf who’s silver with age.) A white Gray wolf normally has creamy undertones and not many silvers and greys.

White Lady: https://i.ytimg.com/vi/IkvpNMZYbxY/maxresdefault.jpg

Anyway, if you ever get to the point of considering new coats, I hope you make it an open discussion so that we can express what we want to have.

I love this update very much.

[WolfDragonPlasma]

Oh my gosh, you have no idea how hard a squeed when I saw this video pop up in my notifications.

Genetics is one of my favorite subjects (Punnett Squares are my favorite aspect of it), and I'm so excited to see it going into the game!

Also, I learned something new today while watching that video. I knew that there was such thing as a "lethal white" gene that exists in other animals (horses especially) but I have never heard of a "lethal black" gene, and in wolves no less! You guys aren't even finished with the new game and already I've been learning a lot about wolves lately XD

Keep up the great work team!

EDIT:

I love games that have genetics in them! I have a suggestion that there could be a small chance for a puppy to inherit his colour from an ancestor. It would be a cute surprise if my mate and I are both white, and one of our puppies inherits a black coat.

Unfortunately, that's not exactly how genetics works. Since the allele for black coats is dominant over the grey coat allele, at least one of the parents would need to have that black allele in order to pass the black coat color to the offspring. Unless through spontaneous mutation, you can't produce a "Kk" from two parents with "kk".
Unless one of those white wolves had some serious highlighting going on to hide the fact that it was black, which, I'm not sure if that's a thing that happens in reality.

[Medenagen]

* If a wolf has two big Ks (KK), then it is black…but it’s probably also dead, since this combination is usually fatal before birth.  

A gene structure commonly bred for in domestic dogs is lethal in wolves? Fascinating and weird.

[Noctis_]

I think it's interesting that although black is dominant over the gray coat color, there are still more gray wolves than black ones. I'd be willing to bet that the KK genotype being lethal has something to do with that.
It would be rather unlucky for a black 'KK' player wolf to choose another black 'KK' wolf as a mate... There would likely be no litter.

When your wolf meets a potential mate, you'll be able to learn a little bit about its genetics, and you can decide if it's a good match.

Does this mean players will be able to 'date' potential mates before making a final decision, rather than just selecting during the first social arena encounter?

[DaniBeez]

Gotta take my Pangoli hat off for a second here

That's awesome Dave. Getting kids to think about genetics! I can imagine kids drawing out the squares as they play on scrap paper .

Having taken a minor in this subject in my undergraduate, I have one suggestion that might aid reader's understanding if they are unfamiliar with genetics: a common misconception about punnett squares is that each of the four small boxes corresponds to one pup/offspring in a litter of four. It may be helpful for some to explicitly state somewhere in your post that the whole punnett square represents the probability for each pup in the litter to be born a certain color. You carried out the examples correct, but an explicit statement might help other understand where your percentages came from later in the post .

Haha, I anticipate future players asking for litter color probabilities! I can help them calculate .

Now some food for thought: complex traits like "disease resistance" or "stamina" are not controlled by one gene, but rather a network of many genes/multiple loci that control many physiological processes, making complex traits very hard to study.

For example, what is speed? Is it a higher percentage of fast-twitch muscles? A larger-than average heart size? A more efficient transfer of hemoglobins in the blood? Having more hemoglobins in general? Or any combination of these, and more!

Sometimes the mainstream media has misleading headlines like, "Scientists have discovered that knocking out gene X in mice causes them to live twice as long, therefore we've discovered the gene for aging!". The reality is that changing the expression of that one gene X probably caused some genetic pathway with multiple genes in it to shut off or be disrupted somehow. So for the sake of the game, simplifying complex traits to one locus is the only way to make them heritable!

But overall well done and good on you for giving it a go!

[Koa]

DUDE YESSS!!! THIE IS SOOO AWESOME AND THE PUP"S OMGOSSSH THEY LOOK LIKE LIL JELLYBEANS!!!! SWEEEE THERE SO CUTE CREDIT TO THE ANIMATOR!

Please do not post in all caps.

Also Dave if I ever need a voice narrator for any wildlife related work I do in the future, I know who I’m going to ask!

[Jeames]

YES YES YES! I love this! This is amazing!
The game's only getting better and better!