Genetics and Variations

What is the probability that the offspring of a homozygous dominant individual and a homozygous recessive individual will have the dominant phenotype?

• 25 %
• 50 %
• 75 %
• 100%

Mendel’s finding that the inheritance of one trait had no effect on the inheritance of another became known as the 

• law of dominance.
• law of universal inheritance
• law of segregation
• law of independent assortment

The law of segregation explains that

• alleles of a gene separate from each other during meiosis
• different alleles of a gene can never be found in the same organism
• each gene of an organism ends up in a different gamete
• each gene is found on a different molecule of DNA

Refer to the illustration above. The genotypic ratio of the F₁ generation would be 

• 1:1:1
• 1:3:1
• 3:1
• 1:2:1

The phenotype of an organism

• represents its genetic composition
• shows the traits that are actually expressed
• occurs only in dominant pure organisms
• cannot be seen

If an individual has two recessive alleles for the same trait, the individual is said to be

• homozygous for the trait
• haploid for the trait
• heterozygous for the trait
• mutated

Refer to the illustration. The genotype represented in box 2 in the Punnett square would

• be homozygous for freckles
• have an extra freckles chromosome
• be heterozygous for freckles
• have freckles chromosomes

How many different phenotypes can be produced when the inheritance reflects incomplete dominance?

• 1
• 2
• 3
• 4

In rabbits, black fur (B) is dominant over brown fur (b). Consider the following cross between two rabbits.
The phenotype of the offspring indicated by box 3 would be _____________ while the genotype would be____________________.

• Bb;  brown
• Black;  Bb 
• brown;  Bb
• Bb;  black   

The phenotype represented by box 6  is ________________ while the genotype  is_________________.

• yellow, inflated;  ggIi
• yellow, constricted;  ggii
• green, inflated;  GgIi
• green, constricted;  GGii