Question

1. A genetic cross in which the inheritance of two traits is observed is called a A) Dihybrid cross. B) Monohybrid cross C) Backeross D) Testcross 2. For single crossovers, the frequency of recombinant gametes is half the frequency of crossing over because A) A testeross between a homozygous and heterozygote produces 1/2 heterozygous and 1/2 homozygous progeny. B) The frequency of recombination is always 50%. C) Each crossover takes place between only two of the four chromatids of a homologous pair. D) Crossover occur in about 50 % of meiosis. 3. In analyzing the results of a three-point testeross, a student determines that the interference is -0.23. What does this negative interference value indicates? A) Fewer double crossovers took place than expected on the basis of single-crossover frequencies B) More double crossovers took place than expected on the basis of single-crossover frequencies C) Fewer single crossovers took place than expected. D) A crossover in one region interferes with additional crossovers in the region. same 4. A genetic map shows A) The location of genes on chromosomes B) The relative distance between genes on chromosomes. C) The genetic relationships between individuals in a family D) Both A and B S. Genetic distances shown on a genetic map are obtained by determining the A) Number of chromosomes in the genome. B) Location of chromosomes in the nucleus. C) Number of base pairs between restriction sites. D) Frequency of recombination between genes. Amale affected with an X-linked dominant trait will have what proportion of offspring 6. affected with the trait? A) 1/2 sons and 1/2 daughters. B) All sons and no daughters c) All daughters and no son D) 3/4 daughters and 1/4 son.

Answer 1

1. Answer is A) Dihybrid cross

2. Answer is C) Each crossover takes place between only two of the four chromatids of a homologous pair.

3. Answer is B) more double crossovers took place than expected on the basis of single crossover frequencies.

4. Answer is D) both A and B

because genetic map is graphical representation of the arrangement of genes on a chromosome that illustrates the location of gene on chromosomes and relative distance between them.

5. Answer is C) Number of base pairs between restriction site

6. Answer is D) All daughter and no sons

When a male is affected with x linked dominance, all his daughters will be affected, but none of his sons will be affected.