Genetics 1

consider the following genotypes of the offspring of two heterozygous brown goats. The ratio of brown to white offspring in this case would be

• 1:3

• 2:2

• 3:1

• 3:4

calculate the probability of a homozygous dominant (BB) offspring resulting from a cross between two parents with the genotype Bb

• 1/100

• 1/2

• 1/4

• 7/10

The production of pink flowered plants from a cross between a red flowered plant and a white flowered plant is an example of

• multiple alleles

• complete dominance

• codominant inheritance

• incomplete dominance

The punnett square shown presents a cross between two piranha. Both parents have large teeth. According to the chart, which combination describes the offspring expected from the cross.

• 50% large- toothed and 50% small-toothed

• 75% small-toothed and 25% large-toothed

• 75% large-toothed and 25% small-toothed

• 100% large-toothed

If both a mother and a father carry a dominant gene for dark eyes and a recessive gene for light eyes (Bb), what is the likelihood that their offspring will have dark eyes?

• 1 in 4

• 2 in 3

• 3 in 4

• 4 in 4

Among a species of butterflies, the color blue (B) is a dominant trait. If a pure blue butterfly (BB) mates with a pure yellow (bb) what will the offspring look like?

• They will all be blue

• They will all be yellow

• half will be blue and half will be yellow

• about 75% will be blue and 25% will be yellow

In this punnett square used to predict genetic crosses, RR represents the ________of the organism.

• appearance

• chromosomes

• genotype

• phenotype

According to Mendel's Law of Dominance, which statement best describes the result of the cross between parents with genotypes Rr and Rr?

• Only RR offspring will have red flowers

• only Rr offspring will have red flowers

• All offspring with at least on R will have red flowers

• because of the Law of Dominance, all offspring will have red flowers.

in a given hybridization between two flowers, red "R" is dominant, and white "r" is recessive. In a cross between tow white-flowered plants, what statement would BEST describe the offspring?

• 75% of the flowers would be white and remaining 25% would be red

• there would be some variation; most flowers would be white and a few would be red.

• there would be no variation in color. All flowers will be white unless a mutation occurred.

• flower color variation would be equally divided given the homozygous parents: half red and half white.

he trait of “freckles” is dominant and represented by A. No freckles is recessive and represented by a. A researcher crossed two individuals, one homozygous dominant and the other heterozygous for freckles. Based on the data in the Punnett square, the researcher concluded that all offspring would have dominant as well as the recessive alleles. What comment would you make about his conclusion?

• He is correct. Fifty percent of the offspring are heterozygous dominant.

• He is correct. The dominant allele for the trait is preset in all the offspring

• He is incorrect. The homozygous dominant individual cannot provide a recessive allele.

• He is correct. Both parents contribute at least one dominant allele to their offspring.