Gene Linkage Practice Questions Flashcards
What does it mean for two genes to be “linked”?
o A) They are on the same chromosome.
o B) They assort independently.
o C) They are always inherited together.
o D) They are located on sex chromosomes.
o E) They exhibit quantum entanglement.
o A) They are on the same chromosome.
Linked genes:
o A) Always show a 9:3:3:1 ratio in dihybrid crosses.
o B) Are located on different chromosomes.
o C) Deviate from expected Mendelian ratios due to crossing over.
o D) Cannot undergo recombination.
o E) Are always purchased at the same time and have no refunds
o C) Deviate from expected Mendelian ratios due to crossing over.
What is a locus?
o A) A point where chromosomes cross over.
o B) The physical position of a gene on a chromosome.
o C) A pair of homologous chromosomes.
o D) The recombination frequency of a gene.
o E) A type of insect
o B) The physical position of a gene on a chromosome.
Which factor increases the likelihood of recombination between two genes?
o A) The genes are located closer together.
o B) The genes are located farther apart.
o C) The genes are on different chromosomes.
o D) Recombination frequency is unaffected by distance
o B) The genes are located farther apart.
The unit of measurement for genetic distance is:
o A) Kilobase pairs.
o B) Centimorgan (cM).
o C) Map frequency.
o D) Mendel unit.
o E) How many arguments occur at thanksgiving.
o B) Centimorgan (cM).
In a test cross of two unlinked genes, the expected progeny ratio is:
o A) 9:3:3:1.
o B) 3:1.
o C) 1:1:1:1.
o D) 1:2:1.
o C) 1:1:1:1.
For two linked genes, the test cross progeny ratios will:
o A) Always show equal proportions.
o B) Deviate from a 1:1:1:1 ratio.
o C) Exhibit no recombinants.
o D) Follow Mendel’s law of independent assortment
o B) Deviate from a 1:1:1:1 ratio.
If recombination frequency is 20%, what does this indicate?
o A) The genes are unlinked.
o B) The genes are close together.
o C) The genes are 20 centimorgans apart.
o D) There are 20 crossovers.
o C) The genes are 20 centimorgans apart.
A double crossover:
o A) Produces only non-recombinant gametes.
o B) Restores parental combinations of alleles.
o C) Happens only in linked genes.
o D) Occurs between sex chromosomes.
o E) Is required for proper tying of one’s shoes
o B) Restores parental combinations of alleles.
What is the relationship between recombination frequency and physical distance on a chromosome?
o A) Direct relationship.
o B) Inverse relationship.
o C) No relationship.
o D) Random correlation
o A) Direct relationship.
Which chromosome carries most sex-linked traits in humans?
o A) X chromosome.
o B) Y chromosome.
o C) Both X and Y equally.
o D) Neither; they are autosomal.
o A) X chromosome.
X-linked recessive traits are more commonly observed in:
o A) Females because they have two X chromosomes.
o B) Males because they have only one X chromosome.
o C) Both sexes equally.
o D) Individuals with Turner syndrome.
o B) Males because they have only one X chromosome.
Which gene determines male development in humans?
o A) SRY gene.
o B) TDF gene.
o C) XIST gene.
o D) Barr body.
o E) Gene Simmons.
o A) SRY gene.
What is a Barr body?
o A) An inactive X chromosome in female cells.
o B) A site of recombination during meiosis.
o C) The SRY gene product.
o D) A condensed Y chromosome.
o E) Similar to a pub body, but a bit more festive.
o A) An inactive X chromosome in female cells.
Calico coat patterns in cats result from:
o A) Autosomal dominant inheritance.
o B) X-linked inactivation.
o C) Polygenic inheritance.
o D) Codominance.
o E) Nobody really knows.
o B) X-linked inactivation.
