A dihybrid test cross results in a 1.2% frequency of recombination. This implies that:
1. genes are located on sex chromosomes.
2. genes are located on heterologous chromosomes.
3. genes exhibit epistatic two factor interaction.
4. genes are located very close to one another on the same chromosome.
In heterozygous condition, the dominant allele is able to express itself only in one sex. This is a
1. A sex limited trait
2. A sex influenced trait
3. A sex linked trait
4. sex-determining trait.
Which field of genetics is the oldest?
1. Transmission genetics.
2. Molecular genetics.
3. Population genetics.
4. Developmental genetics.
‘Molecular genetics’ will be concerned with
1. Production of a new mutant allele of an interesting gene.
2. Hybridizing different varies of plant species
3. studying general allele frequency in a population
4. classification of newly discovered species
What might be the significance of creating a transgenic mice expressing gene for green fluorescent proteins enabling it to glow green in the dark?
1. They can be a source of pleasure for the kids
2. It served as an effective demonstration that an extra gene could be incorporated into and expressed in most tissues of a model organism.
3. They can be seen by predators in the dark
4. This helps identification of transgenic mice.
Match each item in COLUMN I [genetic disorder] with its description in Column II and select the correct answer from the codes given:
|
COLUMN I |
|
COLUMN II |
A. |
Huntington's disease |
a. |
Inability to metabolize certain lipids, affecting proper brain development and death in early childhood. |
B. |
Tay-Sachs disease |
b. |
Caused by a dominant single gene defect and generally does not appear until the individual is 35-45 years of age |
C. |
phenylketonuria |
c. |
Effects of this recessive disorder can be completely overcome by regulating the diet of the affected individual |
D. |
Cystic fibrosis |
d. |
This results from a defect in membrane proteins that normally function in chloride ion transport |
Codes:
A B C D
1. a b c d
2. b a c d
3. a b d c
4. b a d c
A dominant unit factor (trait) is best defined as
1. The most common trait in the population.
2. The trait that is seen in a heterozygous organism (hybrid).
3. A trait that reappears in the F2 of a monohybrid cross.
4. A trait that causes differential reproduction
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The choice of garden peas was largely responsible for success of Mendel. All the following characteristics made the plant useful for study of genetics except:
1. They are diploid and produce haploid gametes.
2. They have a complex phenotype with much genetic variability.
3. They are relatively small and easy to grow.
4. They produce edible fruit.
What would be true for study of karyotype of an organism, for example, humans?
1. Microscopic analysis could allow identification of unusual cellular structures.
2. An individual could be matched to a forensic sample based on identical karyotypes.
3. A specific gene which causes a genetic disorder could be identified.
4. Genetic disorders caused by chromosomal rearrangements could be diagnosed.
Identify the incorrect statement regarding a sex limited trait:
1. This term refers to a trait controlled by a gene located on the X or Y chromosomes.
2. This is a trait that occurs more frequently in one sex than another.
3. This is an extreme example of a sex influenced trait.
4. This trait is likely to be a secondary sex characteristic.