Biology: genes and alleles: dominance

Tutoring biology, the concept of dominance comes up relating to genetics. The tutor gives a simple explanation.

Continuing with concepts from my post on genes and alleles, dominance seems logical to visit next. The following is a simplification.

Let’s imagine there is a gene that determines if one will want a smart phone or not. (This is hypothetical, of course:) It has two alleles: W and w. (Genetics is case sensitive.) Based on the genetics I learned as a kid, there are a couple of implications from this:

• W supports wanting a smart phone, while w supports the opposite (not wanting one).
• W, being capitalized, is dominant, while w, being lower case, is recessive.

Dominant and recessive come into play when a person inherits W from one parent but w from another. Since W is dominant, said person will want a smart phone. When a dominant and recessive allele are both present, the dominant one is expressed, while the recessive one remains quiet. The only way a person will not want a smart phone is if they are ww: they have inherited w from each parent.

Source:

bio.libretexts.org