Genetics

In humans, B is the allele for freckles and b is the allele for no freckles. Two brothers both have freckles but one of them has both the B and b alleles while the other only has B alleles.

Which statement is true about the brothers?

• They have the same genotype and phenotype.

• They have different phenotypes and genotypes.

• They have the same phenotype but different genotypes.

• They have the same genotype but different phenotypes.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

The gene for white hair (W) is dominant to the gene for black hair (w). A rabbit with genotype (WW) was crossed with a rabbit with genotype (ww), as shown in the Punnett square.

What fraction of the offspring should be expected to have white hair?

• 0

• 1/4

• 2/4

• 4/4

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

What would the parents be from this punnett square?

• Both parents are heterozygous.

• Both parents are homozygous dominant.

• One parent is homozygous recessive and the other parent is heterozygous.

• One parent is homozygous dominant and the other parent is heterozygous.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Cattle can be red, white, or roan (both red and white). What mode of inheritance is this?

• sex linked

• codominance

• incomplete dominance

• multiple alleles

What allele will mask the other allele?

• dominant

• recessive

If brown is dominant (B) and blue is recessive (b) what genotype would a blue organism have?

• AA

• Aa

• aa

Tags

NGSS.HS-LS3-2

Brown (B), White (W), or Palomino (a tan color BW)

If a palomino horse and a brown horse were crossed, what percent of their offspring would have white hair?

• 0

• 25

• 50

• 100

Crossing-over most commonly results in

• genetic diversity

• a new species

• mutations

• a new number of chromosomes

The number of chromosomes can be studied by looking at a-

• Karyotype

• punnett square

• pedigree

• genotype

The genotype of an organism describes the-

• alleles

• physical traits

• chromosome types

• number of chromosomes

Tags

NGSS.HS-LS3-1