PATTERNS OF INHERITANCE

What type of inheritance pattern is represented?

COMPLETE DOMINANCE

One allele is dominant over the other; therefore if an individual possesses one of each trait (heterozygous), then only the dominant trait is expressed.

The white allele is dominant; so

when a black cat & white cat

are crossed; all the offspring are

white

What pattern of inheritance do you

observe?

INCOMPLETE DOMINANCE

When two alleles are mixed and result in a third phenotype which is a blend of the two…incomplete dominance is expressed.

When a black cat and white cat are mated, gray offspring result.

Name the pattern of inheritance observed

A red bull is matedwith a white cow. Theresult is the roan cowpictured

CODOMINANCE

Since both red and white color is expressed in the offspring equally; neither allele is dominant over the other; they are both expressed equally

Below are blood types. What type of inheritance pattern controls our blood types?

Multiple AllelesBlood types are determined by 3 alleles: A, B, O

However, an individual can have only TWO alleles at any one time.

Blood types also show dominance (A is dominant over O; B is dominant over O)

Blood types also show codominance (A and B are both expressed if paired together

Identify this inheritance pattern

POLYGENESSome traits are inherited by many pairs of genes. These traits result in many variations (eye color, skin color, hair color, height)

With these traits, the

majority of individuals

would fall in the middle

range.

Name the pattern of inheritance

A red eye fly is mated with a white eye fly. All the offspring have red eyes. But when two of these red flies are mated; there are 3 times as many red eye flies as white eye flies

HOWEVER: all the white eye flies are males

SEX-LINKEDMales only carry one allele for a sex-linked trait since the allele is only on the X chromosome.

• So recessive sex-linked traits are more common in males than females.

• Females may get the trait, but have a chance that the other X chromosome carries a normal gene