History Main / AllGenesAreCodominant

** There are multiple male tortoiseshells in ''Warriors'', which are incredibly rare (about a one in three thousand chance). At least one of them, Redtail, is also a father, despite almost all male tortoiseshells being sterile.

** Even less realistic is Jon Kent, the son of the Pre-New 52 Superman who was introduced during the events of ''ComicBook/DCRebirth''. Jon seems to have his powers like flight and heat vision almost to the same level as his dad. The rub comes in that Jon's powers are unpredictable and sporadic. at first he'll be invulnerable but then a tumble from a tree will give him a concussion. It seems that as he grows his gene's are fighting and shifting in order to find a more stabilized state. They ''do'' finally stabilize after the ''Black Dawn''' arc, giving him an overall power level that is comparable to, but still weaker than, Superman himself, but his overall potential is a case of HybridPower, with Batman claiming that Jon's full powers will surpass his fathers and potentially grant him abilities that his father may never manifest. His unique genome ''does'' leave him deficient in other areas, particularly [[spoiler:his control over his Solar Flares, which can potentially kill him.]]

** Even more realistic is Jon Kent, the son of the Pre-New 52 Superman who was introduced during the events of ''ComicBook/DCRebirth''. Jon seems to have his powers like flight and heat vision almost to the same level as his dad. The rub comes in that Jon's powers are unpredictable and sporadic. at first he'll be invulnerable but then a tumble from a tree will give him a concussion. It seems that as he grows his gene's are fighting and shifting in order to find a more stabilized state. They ''do'' finally stabilize after the ''Black Dawn''' arc, giving him an overall power level that is comparable to, but still weaker than, Superman himself, but his overall potential is a case of HybridPower, with Batman claiming that Jon's full powers will surpass his fathers and potentially grant him abilities that his father may never manifest. His unique genome ''does'' leave him deficient in other areas, particularly [[spoiler:his control over his Solar Flares, which can potentially kill him.]]

* Defied ([[PlayedForLaughs for laughs]]) in ''WebVideo/FriendshipIsWitchcraft'':
-->'''Fluttershy:''' [[spoiler:Dragon-ness]] is recessive.

* ''Franchise/DragonBall'': At least for Son Gohan, the offspring of a human and a Saiyan was a hybrid who had human psychology (the lack of a drive for battle and general empathy for others primarily) but Saiyan physiology, including the prehensile monkey tail, spiky hair, and superhuman ki control. As the series introduced more hybrids, they became almost totally indistinguishable from humans due to the [[Creator/AkiraToriyama series creator]] forgetting tails existed for Saiyan characters due to his WritingByTheSeatOfYourPants style.

* ''Manga/DragonBall'': At least for Son Gohan, the offspring of a human and a Saiyan was a hybrid who had human psychology (the lack of a drive for battle and general empathy for others primarily) but Saiyan physiology, including the prehensile monkey tail, spiky hair, and superhuman ki control. As the series introduced more hybrids, they became almost totally indistinguishable from humans due to the [[Creator/AkiraToriyama series creator]] forgetting tails existed for Saiyan characters due to his WritingByTheSeatOfYourPants style.

* ''Manga/DragonBall'': At least for Son Gohan, the offspring of a human and a Saiyan was a hybrid who had human psychology (the lack of a drive for battle and general empathy for others primarily) but Saiyan physiology, including the prehensile monkey tail, spiky hair, and superhuman chi control. As the series introduced more hybrids, they became almost totally indistinguishable from humans due to the [[Creator/AkiraToriyama series creator]] forgetting tails existed for Saiyan characters due to his WritingByTheSeatOfYourPants style.

** There are other half-demons in the series who look more like one parent than the other. Jinenji's demonic heritage is unspecified, but he is over ten feet tall and has a beastial face, while Shiori the half-bat-demon looks almost completely human (aside from her white hair, purple eyes, and dark skin for a Japanese child who spends most of her daylight hours indoors), and almost nothing like her demonic grandfather whose powers and duties she inherited. This is complicated somewhat by the fact that some full demons have a human form and an animal form that they can magically switch between, and it's unclear if the vastly dissimilar phenotypes are influenced by inheritable differences.

* Kryptonian/Human Hybrids Follow this trope perfectly in any alt universe or future story that shows Franchise/{{Superman}} with children. Superman's children with Lois have his powers and weaknesses at half strength. Their children (when they breed with humans) are 1/4th strength and so on. In one Elseworlds, Superman's ancestor landed during the American Revolution, crushing it and creating his own British empire. The story is set in the present where Kal-El's genetics are so watered down, that he has no powers at all and his father was only marginally superhuman.

* All Genes Are Co-Dominant: The hybrid gets a half deal on ''all'' traits in a kinda-sorta-but-not-really incomplete dominance way. They have half of everything -- from physical appearance, to strengths, to weaknesses. This is probably an attempt at a more realistic aversion of the MarySue route above; but if one of the races has a severe imbalance of power compared with the other, it can have a similar effect overall.

* The MarySue route: The hybrid inherits [[HybridPower both species' strengths and none of the weaknesses]].

* EitherOrOffspring: The child will be either parents species with no hybridization.

In a work with an InterspeciesRomance, the happy couple are very likely to pass on different alleles to the resulting child. The hybrid gets a half deal on ''all'' traits in a kinda-sorta-but-not-really incomplete dominance way. They have half of everything -- from physical appearance, to strengths, to weaknesses.

* ''Literature/{{Xanth}}'' sidesteps the issue of genetics with its "[[LoveIsInTheAir love springs]]," which cause the drinker to fall in love with whoever they see next, and also allow for the birth of offspring even from pairings that should create none. In extreme cases, a shapeshifter is born, but usually the child is just half-and-half. (Among other things, this is where centaurs came from -- explorers led their mares to drink ....)
* In Katherine Kurtz Deryni books, Deryniness is hereditary, but what happens with the offspring of mixed unions is unclear. Sometimes human blood seems to dilute Deryni powers, but sometimes mixed-blood offspring are as powerful as full Deryni.

A MixedAncestry trope.

In a work with an InterspeciesRomance, the happy couple are very likely to pass on different alleles to the resulting child. This is normally where the laws of genetics are thrown out the window in favor of HollywoodGenetics. And in Hollywood, the three things that can happen are as follows:

* EitherOrOffspring: The child will be either parents species with no hybridization.
* The MarySue route: The hybrid inherits [[HybridPower both species' strengths and none of the weaknesses]].
* All Genes Are Co-Dominant: The hybrid gets a half deal on ''all'' traits in a kinda-sorta-but-not-really incomplete dominance way. They have half of everything -- from physical appearance, to strengths, to weaknesses. This is probably an attempt at a more realistic aversion of the MarySue route above; but if one of the races has a severe imbalance of power compared with the other, it can have a similar effect overall.

[[AsYouKnow In real life,]] there are two or more alleles[[note]]Variations[[/note]] for any one gene[[note]]Unless it is a fixed gene, in which case there's only one allele for each gene[[/note]]. These alleles will determine which form of that gene the being will display in their phenotype[[note]]Appearance[[/note]]. If the offspring gets two different alleles for the same gene, there are several different ways that it can go:

* One allele is dominant, and the other is recessive, so the offspring will display the trait that the dominant gene codes for. For example in eyes, the "b" allele codes for blue colour, and "B" for brown. A person with blue eyes will have two copies of the recessive gene, making them bb. However, as B is dominant, you would have brown eyes if you were either Bb (heterozygous) or BB (homozygous). From this, heterozygous people can be 'carriers' of traits without displaying them, which may appear in their children if the other parent either is homozygous for the recessive trait (bb) or is also heterozygous for it.[[note]]Technically, this isn't exactly true. But we use it in biology class, and the only obvious alternative is wet versus dry earwax.[[/note]]
* The alleles are incompletely dominant. Then, the offspring will display a trait that is in between the traits of their parents. (Cross red and white roses, and you'll get pink ones.)
* The alleles are codominant. The offspring display both traits in full. The classic example is blood groups - cross a homozygous type A with a homozygous B and you get heterozygous blood type AB.

Even the MarySue route can be TruthInTelevision, as hybrids often(-ish) do inherit most of the strengths and none or few of the recessive-based weaknesses of the parents.

Mules, for instance, qualify for ''both'' types of this trope. At a glance, they are an intermediate between horses and donkeys in terms of size, coat, ears, and other obvious physical characteristics. [[HybridPower They also tend to actually be more intelligent than either donkeys or horses, are stronger and able to pull and carry a slightly higher percent of their body weight, and have considerably more stamina than either parent.]] Many human cultures have [[ItRunsInTheFamily bred lines of donkeys]] specifically to produce good mules, to take advantage of this [[http://en.wikipedia.org/wiki/Heterosis "hybrid vigor"]].

Also important to the trope: many traits (most types of coloration, for instance) are determined by more than one gene, and the different genes may exhibit different types of dominance. Even if all the genes involved display classic Mendelian dominance, one can still get intermediate phenotypes if some of the pairings come up double-recessive.

* Averted in ''Anime/DragonBallZ'', where the human/saiyan hybrids end up being [[HybridPower at least potentially more powerful]] than full-blooded Saiyans while inheriting their weakness (a tendency to go all weremonkey during a full moon). It's also been confirmed by WordOfGod that tails are specifically not codominant, with Gohan inheriting one but Trunks and Goten being born without.

* Averted big time by the ''ComicBook/RomSpaceknight'' villain Hybrid. Half human and half shape-shifting alien Dire Wraith, his true form is an absolutely hideous gloppy mess that doesn't look much like either, and he possesses psychic powers to rival [[ComicBook/XMen Charles Xavier]] (note that while many Wraiths practice sorcery, they're not noted for being natural psychics). It might be possible to ignore his horrible appearance if he wasn't also sadistically evil.

* This is subverted in ''Fanfic/NeitherABirdNorAPlaneItsDeku''. The Quirk Factor is dominant over the Metagene, as the latter requires a stimulus to manifest while the Quirk Factor will manifest with time. It ''is'' possible to have a natural affinity for magic (and thus be a Homo Magi) and have a Quirk, but it's very rare. Sudden mutations from freak lab accidents bypass all of the above, allowing those with existing Quirks like Barry Allen (better known as Franchise/TheFlash) to obtain a totally different power like SuperSpeed.

** Although the better at magic thing could be explained by the fact that Hagrid was expelled in his third year.
** Averted with the wizard/Muggle blood system. A person is either magical or not, and if they are magical then their level of ability is unrelated to the "purity" of their blood. Although the Death Eaters [[FantasticRacism would love to believe otherwise]].
** Meanwhile, a strange trait pops up in pureblooded families every once in awhile, which results in the occasional Squib child, like Argus Filch or Arabella Figg. This seems to just be a rather rare and unlucky condition. However, Rowling has mentioned something to the effect that Muggleborn witches and wizards could in fact be born from Squib ancestors, suggesting that the same strange quirk that causes loss of magic in some babies also causes the magic gene to reactivate in their effectively muggle descendants. (Or that magic is recessive and that squibs just got unlucky mutations on those genes, WordOfGod to the contrary [[ArtisticLicenseBiology notwithstanding]].)
*** One biology student [[http://mypocketshurt90.tumblr.com/post/27495622491/i-sent-this-paper-to-jk-rowling-explaining-how-the wrote a paper]] explaining how genetics might produce all these traits.
** Some magical traits, such as the ability to talk to snakes, are passed down hereditarily.
* Both applied and subverted in ''Literature/BrokenSky''. The half-Kirin, half-Dominion Jaan has grey skin and yellow eyes, making him physically different from both Dominionfolk and Kirins. [[spoiler: King Macaan]], on the other hand, is half-Kirin, but looks entirely like anyone else from The Dominions.

* ''Literature/RedMoonRising'' plays with this:
** Played straight with half-human vamps, who are fairly similar to both sides of their family tree and share the weaknesses of both species.
** Subverted with any half-wulves, where the wulf genes are dominant and the person is considered either a full-wulf or not a wulf at all depending on whether their parents can afford gene-therapy to suppress the wolf side of their biology (and avert the Change).
** Danny is a subversion. His gene therapy was incomplete, meaning his wulf genes were weakened but not suppressed and his vamp traits are constantly battling it out. At the beginning of the book he's not as stocky as a wulf but not as tall as a vamp. He has wulf hair colour, but vamp eyes and intelligence. [[spoiler: As he comes closer to the Change he grows excessive body hair like a wulf, but the Change itself leaves him mostly cognizant when he should be feral, and doesn't alter his appearance as a normal wulf]].

** Averted with the teeth of half-Klingons K'Ehleyr from ''TNG'' and B'Elanna Torres from ''Series/StarTrekVoyager'', which are human EternallyPearlyWhiteTeeth instead of FangThpeak-inducing Klingon yuckiness. As for the Klingon forehead ridges, played straight with B'Elanna who has a halfway downplayed version, and averted with K'Ehleyr who has ridges indistinguishable from a full-blooded Klingon.
** Averted with the infant son of Seska (Cardassian) and Maje Culluh (Kazon) in ''Series/StarTrekVoyager''. He inherited a half-way Cardassian [[RubberForeheadAlien Rubber Forehead]] but not a Kazon [[RubberForeheadAlien Rubber Forehead]], initially leading people to believe that his father was Chakotay, a human.
** Played straight with Tora Ziyal in ''Series/StarTrekDeepSpaceNine'', half-Bajoran and half-Cardassian; she has a reduced, softened version of the Cardassian forehead ridges (and lacks their rigid shoulder shape) combined with Bajoran nose ridges, and her skin tone is also halfway between grey Cardassian and humanlike Bajoran.

* In ''Series/StarTrekTheOriginalSeries'', it is averted in the case of Spock, who is indistinguishable from full-blooded Vulcans--to humans (Vulcans seem to be able to tell the difference, somehow).
** [[spoiler: The smell, perhaps?]]
** Or perhaps his telepathic 'aura'?
* Averted in ''Series/{{Farscape}}'' by Scorpius. Scorpius looks like something intermediate between a Scarran and a Sebacean, but his two halves are at war with each other, since Scarrans produce excess body heat naturally and Sebaceans are very intolerant of heat, entering a coma-like state when their internal body temperature (which they cannot regulate) gets too high. Scorpius compensates for this disability with an internal cooling apparatus. Scorpius also possesses an ability due to his hybrid nature that is unique to him and not present in either of his parents' species: he can see heat patterns and detect when a being is lying. Interestingly, Scorpius's appearance is similar to the more humanoid, upper-caste Scarrans, rather than the lower-caste Scarran who fathered him.
** With D'argo's half-Sebacean son, Jothee, this trope is played straight. Jothee is essentially the ''Farscape'' version of a Klingon-Human hybrid: physically stronger than a Sebacean but weaker than a full Luxan, possesses his father's stinging tongue but isn't as coordinated with it, and has a weaker sense of smell than a full Luxan that is still superior to a Sebacean's. He even has somewhat intermediate features, though this is partly due to his attempts to make himself look more Sebacean by mutilating his face and tentacles.

* In ''TabletopGame/ArsMagica'', characters with the "Faerie Blood" or "Magical Blood" virtues gain some useful minor powers with no real downside other than looking a bit different.

* Subverted in ''[[VideoGame/WorldOfWarcraft Warcraft]]'', as a Half-Draenei Half-Orc will show that Draenei genes are almost all recessive save for the eyes.
** The reason for this is that she started out being half-orc and half-? (with the implicit assumption being human), with an appearance appropriate for that; Draenei didn't even exist in the lore at that point. It was later realised that there wasn't really any way for her being half-human to make sense, so she ended up half-Draenei since it was the only thing she could be.
*** Her son, a [[HeinzHybrid half-Human, quarter-Draenei, quarter-Orc]], clearly shows signs of all three races: he has glowing eyes, chin tentacles and small horns (draenei); a green skin, small pointed ears and sharp teeth (orc) and a humanlike body and face (ignoring the tentacles). He also [[GodModeSue uses the magic from those three races]]: Arcane magic for humans, Light magic for Draenei and shamanistic Earth magic for Orcs.
* Averted in ''Franchise/DragonAge'' where a human-elf hybrid ends up looking completely human. May or may not have a slightly increased likelihood of being delicate or having magic, but there's no defined category of half-elfishness.
** Played straight after their slight redesign in ''VideoGame/DragonAgeII'', where full-blooded elves now are noticably lither than humans with slightly larger doe-like eyes, whereas they were merely short humans with pointed ears in the first game. One half-elf we see, Feynriel, looks like a subtle blend of both species, being taller and broader than an Elf, but lither and with more pointed features than a Human.

* ''Franchise/TheElderScrolls''
** Averted in individual instances. Several [[InGameNovel in-game books]] and [[AllThereInTheManual backstory details]] state that half-breed children favor their mother's side almost completely, with a few of the father's traits potentially sprinkled in. For example, if an [[SquishyWizard Altmer father]] and [[ProudWarriorRace Nord mother]] produce a child, it wouldn't be a MagicKnight combination of each race. Instead, the child would be almost entirely Nord with the potential of having some Altmeri traits, such as slight points to his ears, higher cheekbones, or a slightly different skin tone.
** Over the course of many generations, however, this trope can eventually occur. This is how the Breton race came to be. Their (human) ancestors were {{Breeding Slave}}s to the Direnni Altmer of High Rock. Over the course of many generations, some of the Elven traits started to come through with greater dominance. This has led the Bretons to be the most magically inclined race of Men in Tamriel at the cost of some of the HumansAreWarriors traits of the other races of Men.

* ''Webcomic/{{Drowtales}}'' specifically attempts to avert this by saying that the MixedAncestry offspring of a Drowolath and a Drowussu are very rare and that each one is a unique blend of the parents. Most half breeds have a skin tone that is some mixture of the two and varying heights and hair colors, with some taking more after one parent than the other.

[[folder:Web Original]]
* Usually averted in ''Literature/ChakonaSpace'', offspring between Chakats and "older model" taurs (wolftaurs and foxtaurs mostly) are always Chakats, usually with their other parent's coat color. Chakat matings with the newer Skunktaurs and Stellar Foxtaurs take after the mother, though Chakats sired by Skunktaurs inherit their father's PsychicPowers. Otherwise hybrids tend to fall under one of three cases:
** Parents are related species such as arctic and red foxmorphs, offspring combine both parent's traits.
** Parents are related but one species is dominant, such as the "new" and "old model" taurs mentioned above.
** Parents are incompatible but one had their gametes genetically reprogrammed to match their mate's, offspring are not hybrids in the slightest.
*** Though in one case a human whose sperm automatically changed to match the species he was having sex with had a Chakat daughter who inherited his ability and mated with a cougarmorph and had a cub who inherited hir prehensile tail and [[{{Hermaphrodite}} reproductive anatomy]]. The ability was the result of the human in question being TouchedByVorlons rather then standard genetic reprogramming though.
[[/folder]]

[[folder:Western Animation]]
* {{Subverted}} in ''WesternAnimation/YoungJustice'' with the Martians: there are two races, White and Green, but mixed-race children [[spoiler:like M'gann]] are either one or the other.
[[/folder]]

A HalfHumanHybrid and HeinzHybrid trope.

In a work with an InterspeciesRomance, the happy couple are very likely to pass on different alleles to the resulting Half-Human Hybrid. This is normally where the laws of genetics are thrown out the window in favor of HollywoodGenetics. And in Hollywood, the two things that can happen are as follows:

* The MarySue route: The Half-Human Hybrid inherits [[HybridPower both species' strengths and none of the weaknesses]].

** There are other half-demons in the series who look more like one parent than the other. Jinenji the half-horse-demon is over ten feet tall and has a literal horse-face, while Shiori the half-bat-demon looks almost completely human (aside from her white hair, purple eyes, and dark skin for a Japanese child who spends most of her daylight hours indoors), and almost nothing like her demonic grandfather whose powers and duties she inherited. This is complicated somewhat by the fact that some full demons have a human form and an animal form that they can magically switch between, and it's unclear if the vastly dissimilar phenotypes are influenced by inheritable differences.

* AllGenesAreCodominant: The hybrid gets a half deal on ''all'' traits in a kinda-sorta-but-not-really incomplete dominance way. They have half of everything -- from physical appearance, to strengths, to weaknesses. This is probably an attempt at a more realistic aversion of the MarySue route above; but if one of the races has a severe imbalance of power compared with the other, it can have a similar effect overall.

** Even more realistic is the New 52 Superman that crossed over from new earth. His son Jon seems to have his powers like flight and heat vision almost to the same level as his dad. The rub comes in that Jon's powers are unpredictable and sporadic. at first he'll be invulnerable but then a tumble from a tree will give him a concussion. It seems that as he grows his gene's are fighting and shifting in order to find a more stabilised state.

* Averted in ''Franchise/TheElderScrolls'', where [[AllThereInTheManual according to the lore]] half-breed children generally favor the mother's side almost completely. They are also very rare, especially since elven races (roughly half of those available) have a very low birth rate to begin with ([[NecessaryDrawback to balance out their long lifespan]]).

** Meanwhile, a strange trait pops up in pureblooded families every once in awhile, which results in the occasional Squib child, like Argus Filch or Arabella Figg. This seems to just be a rather rare and unlucky condition. However, Rowling has mentioned something to the effect that Muggleborn witches and wizards could in fact be born from Squib ancestors, suggesting that the same strange quirk that causes loss of magic in some babies also causes the magic gene to reactivate in their effectively muggle descendants. (Or that magic is recessive and that squibs just got unlucky mutations on those genes, WordOfGod to the contrary [[YouFailBiologyForever notwithstanding]].)

* Averted in ''Anime/DragonBallZ'', where the human/saiyan hybrids end up being [[HybridPower at least potentially more powerful]] than full-blooded Saiyans while inheriting their weakness (a tendency to go all weremonkey during a full moon).

* Human height works in many ways similarly to the skin colour example above, but is complicated by the effect of sex. Still, a person with both tall and short people in their ancestry is likely to end up somewhere in the middle, but it's possible for a person to be taller than either parent, or shorter than either parent.
** It's even possible for parents who are both clinically dwarfs to have children of regular height, and vice versa. [[Series/{{Seinfeld}} Mother Nature's a MAD scientist, Jerry!]]