Mendelian Traits

In this class, we will use all capital letters to indicate incompletely dominant alleles. In this example, the _______ is incompletely dominant over _______, so flowers with genotype RW have the phenotype _______.

• R, W, pink

• W, R, white

• R, W, red

• W, R, purple

Answer explanation

In this example, R (red) is incompletely dominant over W (white), resulting in RW genotype producing a pink phenotype. Therefore, the correct answer is R, W, pink.

Tags

NGSS.HS-LS3-2

________ as two alleles sharing space; both phenotypes are partially seen.

• Codominance

• Incomplete Dominance

• Recessive

• Dominant

Answer explanation

Codominance occurs when two alleles are expressed equally, resulting in both phenotypes being visible. This contrasts with incomplete dominance, where a blend of traits is seen. Thus, the correct answer is codominance.

This cow has genotype RW because she has a _______ gene and a _______ gene, and the alleles are codominant.

• red, white

• black, white

• brown, black

• yellow, red

Answer explanation

The cow's genotype RW indicates it has one red gene and one white gene. Since the alleles are codominant, both colors are expressed, making 'red' and 'white' the correct answer.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette (black and white spotted). Match the following genotypes to their phenotypes

• Black feathers

• BW

• White feathers

• BB

• Erminette (Black and white feathers)

• WW

Tags

NGSS.HS-LS3-1

Black hair color is dominant to white hair color in mice. Determine the phenotypic ratio for the offpring of a heterozygous black mouse and a white mouse.

• 4 Black: 0 White

• 3 Black: 1 White

• 2 Black: 2 White

• 0 Black: 4 White

Tags

NGSS.HS-LS3-1

The ability to taste the chemical PTC is due to a single gene in humans. Tasters carry the dominant allele T and nontasters carry the recessive allele t. Imagine two heterozygotes have a large family. The phenotypic ratio for tasters:nontasters in their children is __________.

• 9:3:3:1

• 1:1

• 3:1

• 1:2:1

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

Having two of the same alleles for a trait (sometimes called purebred) is known as ____________.

• homozygous

• hetrozygous

• protein

• chromosome

What term refers to mixture or blending of two traits?

• Codominance

• Non-dominance

• Complete dominance

• Incomplete dominance

In humans, having freckles (F) is dominant to not having freckles (f). Two people with freckles get married and give birth to three children. Two of the kids have freckles and one does not. Both parents must have which genotype?

• FF

• Ff

• ff

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

What is the name for a cross that examines the inheritance of two traits?

• incomplete dominance

• codominance

• monohybrid

• dihybrid