Genetic Traits and Inheritance Patterns

This tutorial explains incomplete dominance, where neither allele is dominant, resulting in a blend of traits in the phenotype. Examples include Andalusian Fowl, where crossing black and white chickens results in blue offspring, Four O'clock Flowers, where red and white flowers produce pink, and human hair color, where curly and straight hair parents produce wavy hair offspring. The tutorial also explains the use of different letters to represent alleles in incomplete dominance and the typical 1:2:1 ratio of phenotypes and genotypes in such crosses.

What is the result of incomplete dominance in terms of phenotypic expression?

• Neither allele is expressed

• A blend of both alleles is expressed

• Both alleles are expressed equally

• One allele completely masks the other

Which of the following is NOT a characteristic of incomplete dominance?

• Blending of traits

• One allele is completely dominant

• Use of two different letters for alleles

• Three different phenotypes

In the example of Andalusian Fowl, what color results from crossing pure black and white chickens?

• Black

• White

• Blue or gray

• Speckled

In the Andalusian Fowl example, what must be true about the parent chickens?

• They must be heterozygous

• They must be of different species

• They must be purebred

• They must be hybrids

What is the phenotype of the heterozygous condition in Four O'clock Flowers?

• Yellow

• Pink

• White

• Red

What color does the homozygous RR condition produce in Four O'clock Flowers?

• White

• Pink

• Red

• Blue

In the example of human hair, what is the phenotype of the heterozygous condition?

• Curly hair

• Straight hair

• No hair

• Wavy hair

In the human hair example, what does the homozygous HH' condition result in?

• Baldness

• Wavy hair

• Straight hair

• Curly hair

What is the genotypic ratio for the offspring in the human hair example?

• 2:1:1

• 1:1:1

• 1:2:1

• 3:1

What is the phenotypic ratio for the offspring in the human hair example?

• 2:1:1

• 1:1:1

• 1:2:1

• 3:1