These custom items are usually treated as dominant, and they have additional effects on genetics.

The Sims 2 allows the creation of custom hair, eyes, and skin tones, and many are available for download. So, it's possible for the child of an alien-Sim hybrid to receive and carry the alien-skin gene while expressing a normal skin tone and then have a green-skinned child.Īdditionally, for cats and dogs created in CAS with hetero-chromatic (two different-colored) eyes, only the phenotype displayed in the pet's right eye will be present in their genetic code. If neither parent is homozygous for the alien skin tone, and the baby gets both that gene and a gene for a normal Maxis skin tone, the baby may express either gene while carrying the other as a recessive. The alien skin tone does not appear to be truly dominant unless one parent is homozygous for it. Like custom skin tones, it is outside the 1-4 range, and is generally treated as dominant, but how this is expressed depends on other conditions. The alien skin tone appears to be a special case. While one will be shown as 'dominant' and one as 'recessive', the game itself does not treat any normal skin tone as dominant. In SimPE, these genes will be shown as 'SkintoneRange'. For example, a baby who gets a gene for tan skin and one for dark skin may have tan, medium, or dark skin. Within that range, all skin tones are equally likely, and which one the baby has is determined at random. However, if a Sim receives two genes for normal Maxis skin tones, those genes define the ends of a range in which 1 is light skin, 2 is tan, 3 is medium, and 4 is dark. It should be noted that, while alien eyes are dominant, the alien eyes will look identical to brown ones, should the Sim not also express the alien skin tone. The other will be carried as a recessive and will be shown as such in SimPE. That color will be visible, and that gene will show as 'dominant' in SimPE.

However, if the baby gets two dominant (or recessive) genes for eye color or hair color, one will be randomly selected as 'dominant'. If a baby gets a dominant and recessive gene for eye color or hair color, the dominant color will always be visible.

The game considers certain eye colors and hair colors as dominant and some as recessive.

Sims 4 pet genetics mod