Non-Mendelian Inheritance Patterns

Non-Mendelian
Inheritance Patterns

​Non-Mendelian Genetics

• Patterns of inheritance in which traits do not follow Mendel’s laws

• Many traits have more complicated modes of inheritance than just simple dominant versus recessive with two alleles

Non-meNdelian Patterns of Inheritance

Patterns of Inheritance Other than Complete Dominance

• Codominance

• Incomplete Dominance

• Multiple Alleles

• Sex-Linked Inheritance

• Polygenic Inheritance

• Epistasis

Multiple Choice

What does a Punnett Square reveal?

• Chances for offspring to inherit a trait

• How many parents a child has

• Your chances of having a male or female baby

• Human Genome

​Co-Dominance

a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual.

Draw

Draw the offspring of a black cat (BB) and white cat (WW), if their traits are co-dominant.

​Incomplete Dominance

a form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype

Draw

Draw the offspring of a Straight Haired Cat (SS) and Curly Haired Cat (CC) if the Alleles have incomplete dominance.

Match

Match the following

• Dominant

• Recessive

• Genotype

• Phenotype

Allele that is always expressed

Allele that is masked when dominant allele is present

Genetic makeup of an organism

Physical characteristics of an organism

• Allele that is always expressed

• Allele that is masked when dominant allele is present

• Genetic makeup of an organism

• Physical characteristics of an organism

Match

Match the following

• homozygous

• heterozygous

• phenotype

• genotype

• allele

having two identical alleles for a particular gene

having two different alleles for a particular gene

the physical characteristics of an organism

the genetic makeup of an organism

alternative forms of a gene

• having two identical alleles for a particular gene

• having two different alleles for a particular gene

• the physical characteristics of an organism

• the genetic makeup of an organism

• alternative forms of a gene

​Multiple Allele Inheritance

Multiple Allele inheritance means there are more than just 2 alleles

We will use Blood Typing as an example

​Blood Types

Humans have these blood types: A, B, AB, O
Possible Genotypes:

A= AA or AO * can be also represented as I^AI^A or I^Ai = A
B= BB or BO I^BI^B or I^Bi = B
O= OO ii = O
AB= AB I^AI^B = AB

​Rules for Bloodtyping

Both A and B blood types are Co-Dominant in heterozygous individuals


Both A and B blood types are Dominant to O blood type.

Draw

Cross an individual with AA blood and an Individual with BB blood.

Match

Match the following

• AA

• BB

• O

• AB

• AO

I^AI^A

I^BI^B

ii

I^AI^B

I^Ai

• I^AI^A

• I^BI^B

• ii

• I^AI^B

• I^Ai

Multiple Choice

What is the most probable blood type to result from a cross between AO and BO?

• A

• B

• AB

• O

• They are all equally probable

Sex-Linked Disorders

• Caused by the

presence of an allele
on the X sex
chromosome

• Examples:

- Colorblindness- found in 1 in

10 males and 1 in 100 females.

- Hemophilia- does not allow

normal blood clotting to occur

- Muscular dystrophy- results in

the progressive weakening and
loss of skeletal muscle

If mom is carrier and Dad is
normal, boys get the disease

instead of girls

Sex-Linked Recessive

• Disease is rare in the family (only a few

affected family members)

• Disease often skips generations
• Males are more often affected than

females

• Affected fathers DO NOT pass on to

their sons!(Why??)

• Examples: Hemophilia, Duchene Muscular

Dystrophy, Colorblindness

Sex-Linked Recessive Example

Match

Match the following

• Universal Donor

• Universal Recipient

• Antigen

• Antibody

• Blood Cells

Type O

Type AB

Marker on cells

produced by your body to fight invaders

carry oxygen to your cells.

• Type O

• Type AB

• Marker on cells

• produced by your body to fight invaders

• carry oxygen to your cells.

How to determine the pattern of

inheritance in a pedigree:

1.

If there are way more males than females affected
(shaded in,) than the pedigree is tracing a
Sex-Linked trait.

2.

If not, look for two parents that are the same shade
that have a child who is different from them. Label
that child homozygous recessive (Ex. rr) and the
parents heterozygous (Ex. Rr)

a.

If the child was shaded, the pedigree is tracing an
Autosomal Recessive trait.

b.

If the parents were shaded, the pedigree is tracing an
Autosomal Dominant trait.

Match

If (A) represents a normal Allele and (a) represents a Colorblind Allele, match the following:

• Female Carrier

• Normal Female

  (Non-Carrier)

• Colorblind Female

• Normal Male

• Colorblind Male

X^AX^a

X^AX^A

X^aX^a

X^AY

X^aY

• X^AX^a

• X^AX^A

• X^aX^a

• X^AY

• X^aY

Multiple Choice

Traits controlled by genes located on the ___ chromosome are sex-linked traits. Because males only have one of this type of chromosome, they are more affected by harmful recessive genes on this particular chromosome.

• X

• Y

Multiple Choice

In fruit flies, eye color is a sex linked trait. Red (R) is dominant to white (r). What is the sex and eye color of flies with the following genotype: X ^r Y ?

• male with red eyes

• female with red eyes

• male with white eyes

• female with white eyes

Polygenic Trait

an inheritance pattern in which the trait is controlled by many (poly) genes

Ex. Skin color - many genes control it!

Poll

It takes many different genes, on different chromosomes to determine height. Which inheritance pattern would explain height?

• polygenic traits

• multiple alleles

• codominance

• incomplete dominance

Multiple Choice

What type of inheritance is determined by multiple genes located at different loci on different chromosomes and there can be a range of traits?

• Codominance

• Incomplete dominance

• Polygenic traits

Multiple Select

What do you get when you cross A black lab (BBEe) x yellow lab (bbee). Check all possibilities

• Black lab puppies

• Chocolate lab puppies

• Yellow lab puppies

Multiple Choice

______ is the genetic occurrence in which two genes interact. One gene may 'suppress' another gene.

• Epigenetics

• Epistasis

• Genomics

• Trasnsmutations