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?
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