Non-Mendelian Genetics in AP Biology

Definition

Non-Mendelian genetics refers to any pattern of inheritance in which traits do not segregate in accordance with Mendel's laws. These include traits controlled by multiple alleles, genes that exhibit co-dominance or incomplete dominance, and genes located on the sex chromosomes.

Related terms

Multiple Alleles:

This is when there are more than two possible alleles for a particular trait. For example, human blood types (A,B,O) are determined by multiple alleles.

Co-Dominance: This is when both alleles for a gene are fully expressed in the phenotype. Like if you mixed red and white paint together and got spots of both colors instead of pink.

Incomplete Dominance:

This occurs when neither allele for a trait completely masks the other, resulting in an intermediate phenotype. It’s like mixing red and white paint to get pink.