Thanks nine realms for ruining yet another thing I praised about the original. These new dragon's genetics make no sense so imma get to work on fixing their genetics hehehe. and will take that time to also make them less inbred as well. Two birds one stone yeee :D
Nine realms new night lights make no absolute sense in genetics, a thing I praised about past fury dragon designs, that had surprisingly realistic genetics.
Ofc it doesn't matter, its a fictional dragon show, but HTTYD always had very ''realistic'' dragons, or at least as realistic as they can get. Especially in behavior, but I'd like to point out it is true most creatures would need tail fins to take off, otherwise the tail would create a weight putting them down, not to mention tail fins add lift to the tail, which is often used as a directional tool by flying creatures. Genetics making sense just added onto that pile and as a genetics nerd it made me happy.
Nine realms already ruined a lot of things about the OG, some Wayyyy worst then some silly genetics, obviously, but hey, I'm best placed to rant about the genetics then the other messy things so that's what I'm gonna do. Be a petty genetics nerd, for the fun of it.
I will divide this post in multiple section to make reading this wall of text less painful.
Also you might want to refer to this post i made about why fury genetics made a lot of sense before the new nine realms season arrived, and why it doesn't anymore. If it still doesn't help you, it will still be needed to understand what the hell imma be ranting about during the rest of the post, such as explaining in further detail why it doesn't make sense anymore. and also, cool drawings.
1.Why white spotting dosen't make sense anymore
fury dragons were always inspired by cats, so the white spotting model of cat is the main one i base myself off of here. Regardless, white spotting always has similar main rules in all species that share the gene, even if some details about it can change, mostly in the direction the white spotting development tends to take during the fetus' development. In nearly every case tho, white spotting starts developement at the bottom (belly, chest, sometimes face) of the creature, and goes upward in a certain way, that can vary depending on species. Furies seem to follow the same exact as cats, with the main difference being mitted level having high belly white, which cats can't. I mostly attribute this to the fact this is a mistake a LOT of people make, even in actual cats, but since furies are NOT cats, i let it pass as a different rule of how the ws works ;)
I'd also like to point out that white spotting is only ONE form of pigment loss (which causes white patterning) possible in biology. It is the cause of white in most species we are familiar with (cats, dogs, cows) but it is NOT the only way for animals to loose pigment. In fact, cats have separate genes (being much rarer) that can also cause pigment loss. Most notably albinism genes (CC). How do I know furies have white spotting specifically? Most pigment loss genes are not a spectrum, and do not develop on fetuses during its growth. Their pigment loss would be more 'fixed' in a single type of pattern, which seeing the original night lights, it is clearly not. It would also most likely not create a mix of each parent's spotting level in each offspring. It would be either one or the other. If light furies were white because of albinism, when Toothless had kids with one, the kids would either have gotten albinism and being also white, or not have gotten it and be black. (or if colorpoint is a thing then they could be colorpoints too, since colorpoint comes from albinism.) This makes it clear light furies' white comes from them having full white spotting, (WsWs) night furies would then be furies with no white (ww), and night lights are a mix of both (Wsw).
2.Why body shape dosen't make sense anymore
the body shape found in the furies and its genetics accuracy was the thing I was the most surprised about. it used codominance, a very poorly known (despite being VERY important) rule of genetics, and does it skillfully. Codominance is an alternative relation between dominant/recessive genes. The ''classic'' relation will have any dominant gene override the recessive gene in case of heterozygote genes. Heterozygote genes will share both the recessive and dominant allele. (for example, the recessive white spotting gene is w (the 'no white' gene) and the dominant one is Ws (the 'white' gene). So Wsw would the heterozygote white spotting gene. However, both genes we're looking at in furies here are codominant genes, meaning the recessive and dominant gene will both express themselves at the same time in case of heterozygote genes. This cause the night lights being half and half (white/black) instead of either black or white, for example. (IF Wsw WAS a classic gene they would all be white like their mother since she carries the Ws (dominant) gene.)
The Body shape in furies also seem to use codominance, as nightlights seem to have a body shape that is nor the night fury's, or the light fury's, but a mix of both! Note that this only applies for first gen night lights that come directly from a 'purebreed' light fury and night fury. When bred with other night lights/mixed dragons/a light fury/a night fury, a nightlight could produce both night fury or light fury shaped offspring, along with mixed/In-between shaped ones, depending on the genes at play/carried. Since they carry those genes from their parents. Overall, it made total sense, and was a very impressive understanding of codominance.
...Or at least it seemed too.
The new night lights shapes are kind of just random shapes that look like previously established fury shapes, with random variation that do not seem to follow any kind of genetic logic. I don't think i need to explain why this dosen't make sense. It seems the designers think codominance goes on forever when you breed animals instead of the genes being able to come back to their homozygote forms.
3.An argument that could be made in favor of the new night lights genetics (and why i personally don't think it makes sense.)
-''But, AF, Evolution'' :(((
yes the nine realms is like 3000 years in the future. However, fundamental logical rules of genetics such as the body shape nonsense. This one especially could NOT be explained with evolution. As for white spotting, however, rules MIGHT have evolved into something else, but despite how different cats and cows are, for example, they still have roughly the same rules, with slight differences such as cows white spotting developement ending at the neck, while cats tend to end at the tail before they become full white. This shows white spotting doesn't evolved into very drastically different rules, like it seemed to have done in the new night lights. Plus, the white spotting here doesn't seem to have an easy 'beginning point' to point out, which is a notable feature of pretty much all white spotting cases. Finally, their is no evolution advantage for these new types of white spotting, in fact rather the opposite. A reason why white spotting tends to start at the bottom in pretty much all species, is because a white belly and black back can be used as double camouflage, so this form of development was favored in evolution. in case of night lights, for example, their white side (bottom) could be used to camouflage during the day like their light fury parents, while the black side can be used to camouflage during the night like their night fury parents. Random splats do not give this effect, making it way less common.
Also i'd like to point out in 3000 years they shouldn't have evolved THAT much. Cats only gained new genes in 3000 for example, and that was only because of human selective breeding. Furies would most likely have kept roughly the same genes, especially considering dragons most likely live even longer then humans, and definitely longer then cats, making room for less generations to evolves. So not that much evolution could have happened, and even if it did, it wouldn't make sense for it to be this way.
4. Now that I explained why it doesn't make sense, imma explain the character designs and its faults one by one :)
5.Thunder
Oh wow he actually makes sense unlike all the rest of his family.
Thunder is the only Nine Realms night light that still has normal genetics, at least for the most part. Like bruh i even included it in the original post about fury genetics, back when everything made sense. Even his 'evolved' tail fin isn't terribly unlikely, tho for personal reasons (plus my evolution argument above) i still prefer the regular fury look for him. He looks like he has a Sharp (night fury) body shape despite being a night light. This makes sense as with the generations and mix of genes, he could very well have gotten a homozygote 'sharp body shape' gene. However due to the reveal of his parents, it now becomes obvious he couldn't have possibly received a fully night fury shape from anywhere. So i'll have him In-between shape like the OG night lights.
6.Shadow
congrats! he makes the second most sense wow!!
Shadow seems like a mitted night light, however he misses the paw markings, which is highly unlikely on mitteds. I'll be adding some sprinkle of white here. He has white spots all over his body, which mitteds and all white spotting genes, cannot have, but it can be explained by a skin condition that also removes pigment, vitiligo. So I'll make sure to give him vitiligo.
His body shape is sharp, like his brother, but his tail is somehow the round (light fury) shape. Which doesn't make sense obviously, as it was previously established the in-between shaped was a well different type of 'mix' of both. This could work if the Bsbs (body shape) gene used incomplete dominance instead of codominance, but as I previously stated it is very obviously codominant, so I'll have to change body shape to make it more coherent. I personally like the round look better on him so I'll have him a round body shape like his mother.
7.The Elder
he... mostly? makes sense lmao
The Elder is logical in terms of white spotting. He's a mitted. The cut at his neck is kind of weird, but that's the kind of design choice I can do myself on white spotted creatures so I let it pass because i'm not a hypocrite. Small whites on wings is possible at this stage so that's also fine.
The body shape is where I have a lot of problems. It looks like a deformed sharp/night fury instead of choosing a particular shape out of the three. This, yes, WOULD make sense in inbreeding lmao, but i'll also delete the inbreeding so heyyyy.
8.Father Night Light
this is where my problems rise.
His white spotting isn't even really close to anything that could exist. So I'll make him a mitted like the elder, which I don't think its confirmed? but I personally believe is his father.
As for body shape, I'll have him be a In-between, to allow round body shape babies (shadow round body shape hc yeeee) and also because DreamWorks seemed to have forgotten they did that for night lights and are now giving them either night fury or light fury traits lmao.
I will give it green eyes since eye color seems hereditary in furies, (unlike cats) and splattertail's eyes must come from somewhere. He's the most black of the parents, meaning the more likely to have pigmented (non-blue) eyes.
9.Mother Night Light
She's the least logical of them ;-;
BLACK ON BELLY GOES AGAINST ONE OF THE MOST COMMON AND IMPORTANT WHITE SPOTTING DEVELOPEMENT RULES LMAO. again, white often starts appearing on chest/belly. Since she does show spots of black on a white body, I'll make her an harlequin.
I do like how they gave her a light fury shape despite being a night light, proving they still understand SLIGHTLY how this gene and heredity is supposed to work. So I'll keep that.
10.Goggles
They actually look like a logical bicolore??? woooooo. and bicolore is actually possible with the genes given here??? WOOOOOOWWWW!!!! As for their body shape, i'll have them In-between like their father and big brother.
11.Splattertail
They look like a weirdly designed harlequin like their mother, so i'll have them be an arlequin too! Just...with slightly bigger spots as harlequins tend to have.
I'll have them round shaped like their mom and brother!
fricking done yeeeeee
12. How imma them not inbred.
Its actually pretty easy. It's confirmed that furies where heavily haunted to near extinction at one point (mostly night furies, but light furies might have also suffered from it since they also seem rare.) They would have more difficulty finding mates, making them mate in-between (sub)species like Toothless X light fury. This would have had other night lights to be born, before their night fury parent died off. Toothless being the last one, and also having babies with a light fury. Their night light babies then could mate with other night lights. These night lights also carry black (pigmented) gene without them being related. This means the black (pigmented) gene can be kept without inbreeding!!!!! (and it all makes sense too.)
so here we go, i created a logical explanation making them not inbred. Hooray.
Id also like to note this perpetuation of the black gene means night furies could 'come back'. They wouldn't be actual night furies, aka 'purebreed' like toothless and the ones that lived in the past, but if two low white spotting night lights have babies, the babies have a 25% chance of having no white spotting. This gives them a pure black coat like night furies did. If they also happen to inherit a sharp body shape, which would be preserved in the same way the black coloration did, they would basically look exactly like a night fury phenotype (on the outside) wise. On the inside (genotype) they would still not be 'purebreed' tho, so the question 'can night furies come back' depends on if you require the night fury to be purebreed, or only for it to share all the required traits. It's a opinion thing at this point.
Final redesigns coming soon (when I'm done drawing them). It will be in the form of a family tree and then maybe extras for more genetic nerdiness O-o.
Hope you enjoyed my silly rant!
-A petty genetics nerd that likes to rant and redesign illogical genetics in fictional kid shows.