Probability Genetics

The Punnett square shows a cross between a heterozygous tall (Tt) and a homozygous short (tt) pea plant. What are the correct genotypic and phenotypic ratios of the resulting offspring?

• genotype: 1:1; phenotype: 1:1

• genotype: 2:1; phenotype: 1:2

• genotype: 3:1; phenotype: 3:3

• genotype: 4:1; phenotype: 1:4

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Examine the Punnett square showing the inheritance of flower color in plants.

If (R) represents the dominant color red, and (r) represents the recessive color white, what is the possibility that the two plants will have white offspring?

• 0%

• 50%

• 75%

• 100%

Tags

NGSS.MS-LS3-2

Examine the Punnett square that shows the probable offspring of a cross between two watermelons where G represents solid green and g represents striped watermelons.

What would be the genotypes for the parents?

• GG x GG

• gg x gg

• GG x Gg

• Gg x Gg

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In pea plants, the trait for green seed pods (G) is dominant over the trait for yellow seed pods (g). Which cross will produce the maximum number of offspring with green seed pods?

• GG × gg

• Gg × gg

• Gg × Gg

• gg × gg

Females-XX; MalesXY.  A couple has 4 girls.  What is the chance the next child will be a boy? (S7L3. a)

• 75%

• 100%

• 25%

• 50%

The likelihood that an event will occur is called ___________.

• trait

• dominant

• probability

• recessive trait

Short tails (T) are dominant to long tails (t). What is the probability of a long-tailed mouse in the cross Tt x tt?

• 25%

• 50%

• 75%

• 100%

In pea plants, purple flowers are dominant over white flowers. A plant that is homozygous for purple flowers is crossed with a plant homozygous for white flowers.

If the offspring from this cross are allowed to self-pollinate (cross with themselves), what will be the ratio of purple to white flowers in the second generation?

• 2:2

• 4:0

• 1:3

• 3:1

The Punnett square shows four combinations of alleles for black fur (B) and white fur (b).

Which genotype should replace the question mark?

• BB

• Bb

• bb

• b

In chickens, the trait for yellow legs (Y) is dominant over the trait for white legs (y). A breeder wants to cross his chickens to have offspring with an equal ratio of chicks with yellow and white legs. Which Punnett square best represents the outcome that the breeder desires?

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