Biology genetics Test

In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue-eyed offspring are produced. If the blue-eyed sheep are mated with each other, what percent of their offspring will most likely have brown eyes?

25%

The probability that Matthew and Jane's first child will be an achondroplastic dwarf is

50%

Which of the following best explains the differences in flower color of the African violets in the greenhouse?

An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center.

In the cross diagrammed above, the expected and observed results are shown. Which of the following best explains the observed results of the cross?

The genes for body color and wing shape are located close to each other on the same chromosome.

Which of the following correctly describes the relationship of the dark-coat-color allele to the albino condition?

It is dominant

The genotypes of Matthew and Jane are best represented as

Mathew- Aa, Jane-aa

The data above represent the results of three different crosses involving the inheritance of a gene that determines whether a certain organism is blue or white. Which of the following best explains the mechanism of inheritance of the gene?

The allele for blue is an X-linked dominant allele because there are no blue male offspring in cross 2.

How would the extra chromosome affect the male offspring produced by the gamete?

The male offspring would have full-color vision, because of the presence of the extra X chromosome.

Which of the following is the most likely explanation of the results?

The two genes are linked on an autosome.

There are white-eyed females in the F2 generation because

these F2 females have two white alleles

Which of the following represents the relative positions of these four genes on the chromosome

CABD

In cross II, the genotype of the dark, short-haired parent is

CcBb

n the pedigree above, circles represent females, squares represent males, and shaded figures represent individuals expressing a specific trait. The expression of this trait is most likely due to which of the following?

Autosomal recessive inheritance

Which of the following statements best explains the data?

Flower color is an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and white cross can best be explained by another gene product that influences the phenotypic expression.

Based on the data in Table I, which of the following best explains why there are no individuals with constricted pods in the F1 Generation?

Inflated pod shape is dominant to constricted pod shape.

Which of the following represents a cross between a white-eyed female and a red-eyed male?

RrXX with two recessive t's X RrXY with a big T

Which of the following best supports the hypothesis that the difference in leaf color is genetically controlled?

The existence of yellow-leaved seedlings as well as green-leaved ones on day 14 in dish B

Which of the following best describes the likely mode of inheritance for the eye-color gene?

The eye-color gene is likely autosomal because males and females have similar phenotype ratios.

The researchers calculate a chi-square value of 4.6 and choose a significance level of p=0.05. Which of the following statements best completes the chi-square goodness-of-fit test?

The null hypothesis cannot be rejected because the chi-square value is less than the critical value.

Which of the following pedigrees most accurately represents a family with a history of Tay-Sachs disease?

The one with one black square and one black circle

Which of the following best explains the cause of the phenotypic variation observed in the butterflies

There was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to.