Genetics Challenge: Incomplete & Co -dominance

Discussion in 'THREAD ARCHIVES' started by Lady Sabine, Mar 9, 2014.

  1. So, we've all been through a high-school level crash course on Mendelian genetics, right? You know, pea plants with different colored flowers or different stem heights? Take the little r and the big R, practice making some hybrids, predict what the offspring will be...
    Well, I'm here to tell you that genetics can be really awesome when you're planning out multiple generations in a family. There are some things, like eye color, that in normal humans that you can't easily predict due to an overwhelming number of genes being involved. Other things, though, like curly hair, can be traced pretty easily.

    Well, all of that is fine, but we're not here for something you probably learned years ago. We're going to deal with something slightly more complicated: codominance & incomplete dominance.
    Codominance is when two traits both express completely. For example, a tulip with red and white codominance would have parts of the petals that are red, and parts that are white.
    Incomplete dominance is when a dominant trait can't completely overcome a recessive allele, and the two combine, making the heterozygous genotype into a brand new phenotype. In this example, the tulip with a dominant red gene and a recessive white gene would come out as pink all over, because the red can't overcome the pink entirely and they mix together.

    Now, how is this useful for roleplaying? Well, if you have a family that is bound together by a specific trait (or combination of traits), as many families are, you might want to figure out why some people have it and some people don't, to better predict what kids will have it- or to work backwards and see which ancestors introduced it to the family tree.
    This is especially useful in fantasy settings. Maybe there's a family with the Vampirism and Lyncanthropy genes both. A homozygous dominant vampire, VV, dies due to blood poisoning. Lycanthropy, however, is recessive ll, so an Ll and a LL would not have the gene. But if you get a Vv ll, incomplete dominance of the V over the l results in a rare vamp-werewolf hybrid, which is the most powerful creature of all.
    Or maybe there's a family that uses magic. Kinetic magic, or being able to manipulate energy, is kk. Being able to manipulate items, or enchantment magic, is ee. So an ee kk would be able to use both types of magic because the traits are codominant.

    DISCLAIMER: this is an oversimplification of a very complex process. I am aware this is not 100% accurate, but I think it will be a fun challenge anyway.

    Your challenge today is to trace out two or more genes across three or more generations of a family, with codominance and/or incomplete dominance coming into play at least once. ^^