Bio 12.3 LESSON

Other Patterns of Inheritance

Learning Objectives

▪ Describe some of the exceptions to Mendel’s principles.
▪ Explain the environment’s role in the way genes

determine traits.

Incomplete Dominance

• Some alleles are neither dominant nor recessive.

• Incomplete dominance: One allele is not completely
dominant over another.

Codominance

• The phenotypes for both alleles are clearly expressed.

• Examples: chicken feather color, human protein controlling
blood cholesterol levels

Multiple Choice

The blending of two traits in which one is not completely dominant over the other is known as ---

• incomplete dominance

• codominance

Multiple Choice

What type of inheritance pattern is shown here?

• Codominance

• Incomplete dominance

Multiple Choice

A calico cat shows both the traits for orange fur and black fur. What kind of allele expression is this?

• Incomplete dominance

• Codominance

Multiple Choice

The green fish offspring in this image is an example of ---

• Incomplete dominance

• Codominance

Multiple Alleles

Many genes exist
in more than two
forms.

Examples: human
blood types, fur
color in rabbits

ABO blood group is an example of multiple alleles, complete dominance, and co-dominance inheritance.

Multiple Choice

Mama Isabella has a blood type of O. Her son, Norman, has also a blood type of O. What is the blood type of Norman's father?

• A

• B

• AB

• O

Multiple Choice

What is NOT a possible genotype for someone with type B blood?

• BB

• AB

• BO

Multiple Choice

What is the genotype of a person with type A blood, who had a father with type O blood?

• AB
• AO
• AA
• OO

Polygenic Traits

• Many traits are produced by the interaction of several genes.
• Examples: eye color in fruit flies, coat color in dogs
• Traits typically show a wide variety of phenotypes.

Multiple Choice

What type of inheritance is determined by multiple genes and there can be a range of traits?

• Codominance

• Incomplete dominance

• Polygenic traits

Genes and the Environment

Environmental conditions can affect gene expression and
influence genetically determined traits.

The phenotype of an organism is only partly
determined by its genotype..

Multiple Choice

The physical appearance of an organisms is its

• Genotype

• Phenotype

• characteristic

• Heterozygous

Multiple Choice

The different forms of a gene are called

• traits

• pollinators

• alleles

• hybrids

Multiple Choice

Examples include skin color and height (the individual's phenotype exists somewhere along a spectrum)

• polygenic inheritance

• multiple alleles

• linked genes

• incomplete dominance

Multiple Choice

AB blood type is an example of what type of inheritance? Both alleles show in the phenotype

• complete dominance

• incomplete dominance

• codominance

• polygenic inheritance

Multiple Choice

A single gene has 3 or more alleles. These are called

• multiple genes

• multiple alleles

• codominance

• polygenic traits

Multiple Choice

The two cows on the top are the parents and the cow on the bottom is the offspring. What is the type of inheritance pattern is being exhibited?

• Incomplete Dominance

• Codominance

• Multiple Alleles

• Polygenic Inheritance