In a testcross, the parent that is homozygous recessive for the genes being studied is called the testcross parent. The parent that has the dominant phenotype of the genes being studied is called the non-testcross parent.
Which of the following is NOT a reason that a testcross is a useful technique when studying the inheritance of a trait?
Select one:
a. Because the testcross parent can contribute only recessive alleles, the alleles contributed by the other parent will be expressed in the offspring of the testcross.
b. The relative frequencies of the different phenotypes among the testcross progeny can be used to map linked genes.
c. The gametes produced by the testcross parent are determined from the testcross progeny.
d. A testcross can determine if an individual with the dominant phenotype is homozygous or heterozygous.
Genes
Recombination
Frequency
A and B
2%
B and C
17%
C and D
4%
A and C
15%
B and D
13%
What is the frequency of crossing-over between A and D?
Select one:
a. 6%
b. 15%
c. 11%
d. 8%
Which of the following statements best describes the events associated with the recombination of genes?
Select one:
a. Crossovers are most likely to occur between linked genes that are close together.
b. If the alleles in gametes after meiosis are different from those in the parents, the gametes are referred to as recombinant.
c. Any two genes located on the same chromosome are called linked genes.
d. If two genes are located on the same chromosome, the alleles on non-sister chromatids of homologous chromosomes will segregate together if a crossover does not occur between the two genes.
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