Polygenic Inheritance

Hair Color What is going

on here?

Polygenic vs. Multiple Alleles Multiple Alleles: Blood Type

Phenotype- A, B, AB, O blood type Alleles IA IB IO

ONE gene, with 3 alleles

Polygenic: Hair color Many genes affecting one trait MANY PHENOTYPES!

Polygenic Inheritance Different genes

contributing to the phenotype.

#4 #12 #13

How do many genes give so many phenotypes? Flower Color

What is going on here?

AABBDD Burgundy Polygenic Inheritance Many contributing

genes to one trait How many genes?

3 How many phenotypes?

6

Aabbdd Light pink aabbdd White

AAbbdd Pink AABbdd Dark pink AABBdd Red AABBDd Dark red

Each “capital” is an additive allele adding to the pigment

How many genes are involved?

Polygenic TraitsQuantitative Traits:

Phenotypes vary in degree Skin color and hair

color Other examples?

Height Eye color Weight

Polygenic Simulation Questions to keep in mind How do parents pass on genes for

height to their children?

Is anyone taller than both of their parents? How can the genes contribute to this?

Class Data 6’1” 5’11” 5’9” 5’7” 5’5” 5’3” 5’1”

Histogram

How can a child be taller than his parents?

Environment Influenced by the genes and environment

Height? Skin color ? Weight?

Exit Ticket Americans used to be the “tallest” nation from

about 1800-1950. Recently many industrialized European countries are now “Taller” ( Holland is #1). Why do you think?

How tall will your child be? Take your height based off the polygenic traits of

the simulation and assume the height of your partner. What possible heights could your child be?