Tirten & Mettalus Genetics

Since tirten evolved from mettalus, they share many genetic similarities. Theoretically, a mettalus and tir could successfully have fertile offspring. If it weren't for their vast phenotypical differences and the social stigma against the idea (and the fact that only a single mettalus lives while tirten do), they could be considered the same species.

Since they share so many similarities, tirten will be outlined in detail. Mettalus will have a section at the end describing the main differences in presentation.

Overall, the genetics of tirten and mettalus are comparable to their distant ancestor, the domestic cat.

Tirten Genetics

Hair Color

  • Black Pigment
    • Black [B]
    • Maroon [M]
    • Brown [Bm]
      • Brown is a combination of black and maroon.
  • Orange Pigment
    • Orange [O]
    • Orange is sex-linked, and is codominant with melanin. An XX tirten that is Oo will display orange and black pigment in their hair. An XY tirten that is OY will display orange coloration. A tirten with black-and-orange hair may also have differently colored patches on their skin, as both pigments have a small impact on skin color.
  • Blue-green Pigment
    • Controlled by the recessive BGP gene [bgp]. When displayed, it overrides both orange and black pigment in the hair.
    • There are two possible colors from this gene.
      • Blue [L]; dominant
      • Green [g]; recessive

  • Dilution [d]

    • Dilution is recessive. It lightens the tone of the hair.

      • Black becomes gray.
      • Brown becomes light brown.
      • Maroon becomes pink.
      • Orange becomes cream.
      • Blue becomes cyan.
      • Green becomes yellow.

  • Caramelizing [N]

    • Caramelization is dominant. It is named for its reddening effect on tirten with black and orange pigment.

      • Black- and brown-haired tirten with caramelization may resemble maroon tirten.
      • Orange haired tirten may have bright scarlet hair in some cases, but the effect is typically less pronounced than with black pigment.

    • Caramelization has less predictable effects on tirten that display BGP.

      • Blue becomes purple.
      • Green becomes magenta.

Hair Pattern

  • White Strand/Spotting [S]

    • This gene can also impact the skin, but typically only displays on the hair unless the spotting is extensive. The most common presentation of this gene is a small lock of white hair on the side of the face, hence the name.

    • It is dominant, but fairly rare.

    • The extent of spotting is polygenetic and mostly unstudied. A tir can have the gene with spotting so minimal that it is never noticed. Others have hair that is completely or almost completely white.

  • Banding [A]

    • A dominant gene, though like white strand, it's fairly rare. It has some modifiers.

      • Unmodified, also known as light-tipped, [U] is dominant. Its name is self-explanatory--tirten with this gene have lighter tips at the ends of their hair.
      • Alternating [t] is recessive. Tirten with this gene have alternating colors on individual strands of hair, giving a striped appearance.

Hair Texture and Length

  • Maximum hair length is genetically determined. There is a lot of variation between individuals, but generally, longer hair [l] is recessive to shorter hair [L].

  • There are multiple genes for curly/wavy hair.

    • Curly hair [CH] is dominant to straight hair [ch]. However, it is only partially dominant. Tirten with only one allele for curly hair [CH/ch] will display it in a less pronounced manner.

    • Wavy hair [WH] is dominant to straight hair [wh]. This gene does not display partial dominance.

    • A tir with both curly hair and wavy hair will be impacted by both genes, resulting in very tight, very textured curls.

    • Longer-haired tirten may appear to have straight hair due to their hair weighing itself down, especially if they are heterozygous for curly hair and do not have the wavy hair allele. The effects of these genes are most visible on short-haired tirten.

    • Though it is easiest to see the impact of these genes on the mane of a tir, they do impact all of their body hair.

Skin Color

  • Skin color is polygenetic. Assume a tir can be any shade between their parents. However, it can be modified by hair color, which may lead a child to be darker or lighter than one or both parents.

    • Black-based hair colors make skin darker.

    • Orange-based hair colors make skin lighter.

    • BGP colors do not impact skin color, but their display (or lack thereof) does not negate the other pigments' impact.

Eye Color

  • Eye color is roughly associated with hair color, similar to skin color. Black-based colors darken the eye color, while orange-based colors lighten them.

  • Inheritance of eye color is difficult to track. Forahen and katiren claim they're influenced by vi (an individual's forsen/"magic" color).

  • It is normal for tirten to have eye colors that would be considered unnatural in humans. Their spectrum of eye colors closely resembles that of domestic cats, with oranges, yellows, and greens being fairly common.

    • They can also have purple eyes, which are associated with the presence of the BGP gene. Carriers of the gene may be identified by this without the need for testing due to this exclusivity. However, many carriers and displayers of the BGP gene have other eye colors. Blue is particularly common.

    • Pink and red eyes, though very rare, have been reported, and are typically accompanied by severe light sensitivity. They are assumed to be recessive.

  • Heterochromia is associated with white strand.

Katir Traits

  • Expression is controlled by the recessive katir gene [kat].

  • Ears and eyes are always altered if the tir is homozygous [kat/kat]. Katiren always have some sort of tail, but it may vary in length.

    • Curled ears (AC) are dominant, but rare.

    • Shortened tails are incomplete dominant [ST], but like curled ears, are quite rare.

  • Katiren tend to have longer canines than most tir.

  • Claws are recessive [ca].

A Note on Features Typically Associated with the Sexes in Humanoids

  • In tirten, features that superficially resemble sex-linked human ones (such as breasts or facial hair) are not linked to sex.

  • Tirten with penises are referred to as vesiren (singular: vesir). Tirten with a uterus, ovaries and/or vagina are referred to as vaniren (singular: vanir).

    • Vesiren are typically XY.

    • Vaniren are typically XX.

  • Breasts are not linked to sex. All tirten can lactate, and some may grow permanent breasts after nursing. Those who have permanent breasts, through nursing or through inheritance, are referred to as xkani. Those without breasts are referred to as xnami (this is also used to refer to a tir who has had their breasts removed).

    • There is no discernable pattern of inheritance, but there are less xkani than there are xnami.

  • Facial hair is rare and recessive [f]. It is not linked to sex.

Differences Between Mettalus and Tirten

Mettalus genetics are nearly identical to tirten genetics, but because they have fur, they display patterns that tirten cannot.

  • Mettalus that display unmodified banding have patterns resembling those of ticked tabby cats.

  • Alternating banding presents with patterns similar to those of classic/blotched tabbies.

  • Curly hair in mettalus resembles Selkirk rex cats.

  • Wavy hair in mettalus resembles LaPerm cats.

Some features are tirten-specific.

  • Mettalus are all xnami. The mutation that causes xkani is tirten-specific.

  • Facial hair is also tirten-specific.

Examples

Simple example: A cross between a brown-haired (Bm) and a maroon-haired (mm) tir results in 50% brown-haired and 50% maroon haired children.

Multi-factor example: A cross between a brown-haired tir with orange patches (Bm Oo) and an orange-haired tir carrying black (BB OY) results in orange haired children carrying black or brown, orange and black haired children, and orange and brown haired children.

Geneset example: A cross between a Bm oY BGPbgp Lg Dd NN Ss aa UU ll CHch KATkat (caramelized long brown haired tirten with curls and white strand) and Bm oo bgpbgp gg dd nn ss aa uu Ll CHch katkat (yellow short haired katir with curls)

  • 50% of offspring will have black hair, 25% maroon, 25% black
  • No offspring will have orange.
  • 50% of offspring will not display blue-green pigment (BGPbgp), 50% will (bgpbgp)
  • Of those that display BGP, 50% will be blue (Lg), 50% will be green (gg).
  • 50% of offspring will display dilution (dd), while 50% will not (Dd)
  • All offspring will display caramelization (Nn)
  • 50% of offspring will display white strand (Ss), 50% will not (ss)
  • No offspring will display banding
  • 50% of offspring will have short hair (Ll), 50% will have long hair (ll)
  • 75% of offspring will display curly hair (50% CHCH, 50% CHch), 25% will not (chch)
  • 50% of offspring will be katiren (katkat), while 50% will not (KATkat)