Genelib

This mod does nothing useful on its own. Install if another mod requires it.

 

This mod provides genetic inheritance support for mods which depend on it. Currently that includes:

Truth and Beauty: Detailed Animals - currently only chickens and goats, more animals planned!

Truth and Beauty: Seasonal Animal Breeding - no genetics, but Genelib provides the seasonal breeding code logic in a way compatible with my other mods

Equus: Wild Horses - horse genes include agouti, extension, tobiano, and more!

The GUI dialog for naming your animals also comes from here. Look at an animal and press "N" to open it. Works with just Genelib for Monoceros, Draconis, Pegasus, and Equus. Installing Detailed Animals will enable this feature for all remaining vanilla and modded animals.

Genetic inheritance

Basics of how genetics work: Each species comes with a number of genes, each of which may come in multiple variants. Every individual animal has two of the variants for each gene, or two identical copies of the same variant. These determine traits such as coat color.

To give a concrete example, let's look at horses. Horses have a gene called extension that determines which type of pigment colors their fur. One variant called E allows for both black and 'red' (a term geneticists use for a range of shades from coppery to golden), while the other one, e, only allows red and not black. Since every animal has two variants of each gene, an individual horse could have E/E (that is two identical copies of E), E/e or equivelantly e/E, or e/e. You'd probably figure a horse with E/E would be partly red and partly black, while a horse with e/e would be fully red, and you'd be right (with some simplification). But what about E/e, that has one of each variant? For that we need to know that E is dominant over e and therefore hides its effects, so the horse would be partly red and partly black just like with E/E. Conventionally the dominant gene is named with a capital letter and the recessive one with lowercase, which makes it easy to remember which one wins conflicts (but sometimes hard to remember what each one actually does).

Ok, but what does all that have to do with inheritance? Well, when two parents produce a foal, they pass on one of their two variants of each gene, chosen at random. So if the mother has E/e, she has half a chance to pass on the E and half a chance to pass on e. And suppose the father has e/e, he passes one on at random and it's going to be e because that's the only one he's got. Putting those together you have half a chance to get a foal with E/e who looks like its mom, and half a chance the foal will be e/e and look like its dad. It doesn't always have to work out this way! Other pairings might get foals with a 100% chance to look like say their mom, and others still might have a chance that the foal will not look like either parent. You can figure out which situations these happen by doing way too many Punnett squares in your local high school biology class.

This horse example of course only applies if you have Equus: Wild Horses installed.

Sex-linked genes

These are only implemented for chickens in Truth and Beauty: Detailed Animals at the moment. Remember how I said each animal has two variants of each gene? That was actually a simplification that these put the lie to. Depending on its species and gender, an animal may have one or two variants - not two different ones or two of the same one, but actually two or only one - matching the sex chromosomes it has.

You may have heard that males have an X and a Y chromosome, while females have two X chromosomes. This is the case for mammals generally (don't mind the platypus). However, birds do things differently. In birds, the male has two Z chromosomes, while the female has one Z and one W. Don't worry too much about the changed names, the important bit is that in mammals, females have two of the same sex chromosome and males have one of each, while in birds it's reversed.