Genetics: Incomplete Dominance and Co-Dominance

The video tutorial covers basic genetics concepts, starting with a simple problem involving eye color inheritance. It explains heterozygous and homozygous genotypes, and how to use a Punnett square to calculate the probability of offspring traits. The tutorial also discusses how environmental factors can influence physical traits like height. It introduces incomplete dominance using a flower color example and co-dominance with horse color, highlighting how different alleles can affect phenotype.

What does it mean if someone is heterozygous for a trait?

• They have two identical alleles for a trait.

• They have more than two alleles for a trait.

• They have two different alleles for a trait.

• They have no alleles for a trait.

What is the phenotype of an individual with a heterozygous genotype for a dominant trait?

• Both traits are expressed equally.

• Neither trait is expressed.

• The dominant trait is expressed.

• The recessive trait is expressed.

In a Punnett square, what is the probability of two heterozygous parents having a homozygous recessive child?

• 1 in 2

• 1 in 3

• 1 in 4

• 1 in 5

Which of the following is an example of a trait influenced by the environment?

• Eye color

• Blood type

• Hair color

• Height

What is the result of crossing a red flower with a white flower in incomplete dominance?

• A pink flower

• A white flower

• A red flower

• A striped flower

In incomplete dominance, what is the genotype of a pink flower resulting from a red and white cross?

• WR

• RW

• WW

• RR

Which genotype represents a homozygous plant for flower color in incomplete dominance?

• RW

• RR

• WR

• Rr

What is co-dominance?

• When neither allele is expressed.

• When one allele is completely dominant over the other.

• When alleles blend to form an intermediate trait.

• When both alleles are expressed equally in the phenotype.

What is the result of crossing a white horse with a brown horse in co-dominance?

• A brown and white spotted horse

• A tan horse

• A white horse

• A brown horse

In co-dominance, how do the alleles contribute to the phenotype?

• Only the dominant allele is visible.

• Only the recessive allele is visible.

• Neither allele is visible.

• Both alleles are visible in the phenotype.