1. Day 4 Non-Mendelian Inheritance
ESSENTIAL QUESTION: How do genes influence the variety of organisms that exist?
Clarifications
Students will use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
Students will identify, analyze, and/or predict inheritance patterns caused by various modes of inheritance.
Content Limits
Items referring to general dominant and recessive traits may address but will not assess the P and generations. F1
Items addressing dihybrid crosses or patterns that include codominance, incomplete dominance, multiple alleles, sex-linkage, or polygenic inheritance may assess the P and generations. F1
Stimulus Attributes
Inheritance outcomes may be expressed in percent, ratios, or fractions.
Scenarios may refer to codominance or incomplete dominance but not both codominance and incomplete dominance.
Punnett squares may be used to predict outcomes of a cross.
Response Attribute
Options may include codominance or incomplete dominance but not both.

2. Incomplete Dominance
Wait! This should have been RED, but incomplete dominance makes it pink
-Neither allele is completely dominant or recessive. The heterozygous will be a blend of the two alleles.
rr: white
RR: Red
Rr: pink

3. Incomplete Dominance Monohybrid
Parents are both heterozygous pink. Rr Rr
P1 ______ X ______
Offspring Genotype r R
1 RR : 2 Rr : 1 rr R RR Rr
Offspring Phenotype
1 Red : 2 Pink : 1 White rr r Rr

5. Codominance Monohybrid
This is when both alleles are expressed fully and separately.

6. Codominance Monohybrid
Parents are both heterozygous for black & white feathers.
P1 ______ X ______ BW BW
Offspring Genotype B W
1 BB : 2 BW : 1 WW
Offspring Phenotype B BB BW
1 Black
2 Black & White
1 White W BW WW

7. Codominance Monohybrid

8. Polygenic Inheritance
A trait produced by two or more genes that each contribute to the same phenotype.
Gene Name
Dominant Allele
Recessive Allele
BEY1
brown
blue
BEY2
GEY
green