Agenda 4/10 Mild, medium, spicy warm up Non-Mendelian patterns of inheritance notes Non-Mendelian practice Homework: 1. Advanced Genetics Video and Notes 2. Chp 15 Reading and Notes (Due Friday)

What are some human traits that do not follow normal dominant/recessive rules?

Co-dominance Co-dominant traits occur when BOTH alleles for a trait are dominant This means that BOTH traits will be expressed Co-captain= both captains, co- dominance=BOTH dominant Examples: Blood type AB, roan cattle, checkered chickens

Incomplete Dominance Incomplete dominance occurs when neither allele is complete dominant This results in the heterozygous genotype expressing a blending of traits Example: Snapdragon flowers

Multiple Alleles Multiple alleles refer to a trait that is coded for by more than two alleles Example: Blood typing in humans A allele, B allele, O allele A and B are codominant O is recessive

Polygenic Inheritance Polygenic traits are traits controlled by more than one gene Example: height, skin color, hair color Polygenic traits typically follow a normal distribution curve

Epistasis A gene in a different locus can affect the expression of a gene at another locus ‘Modifying genes’ Example: coat color in mice

X-Linked Traits X-linked traits are traits that are coded for only on the X- chromosome Men only have one x, so it is more likely that men will be affected by diseases carried on the X- chromosome Women have a second X to ‘cancel out’ 1 damaged ex Example: Hemophilia, color- blindness