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Genetics: Virtual Zygosity (What's a Jamiroquai?) Quiz

Think you’ve got your head wrapped around Genetics? Put your knowledge to the test. Good luck — the Stickman is counting on you!
Q. A dominant allele determines a phenotype when present in

a homozygous individual
a heterozygous individual
an individual with any genotype
option 1 and 3
option 1 and 2
Q. A haploid individual

has one sex chromosome
carries only recessive alleles
has one set of chromosomes
cannot reproduce
is always a male
Q. If two genes are NOT linked, how likely are they to be inherited together?

Q. You identify a single gene affecting three different phenotypes. What is this gene an example of?

Incomplete penetrance
Q. If a trait is 100% penetrant, it means that

all the individuals with a given genotype present the expected phenotype
there is no variation in the trait
the trait is not affected by the environment
more than one gene affects this trait
every individual carries this trait
Q. Examine carefully the pedigree below. Based on the inheritance pattern of this condition, where might its genetic cause reside?


Remember, in pedigrees, men are represented with a square and women with a circle. Roman numerals define generations (I, II, and III), and Arabic numerals (1, 2, and 3) define birth order within each generation. Here, someone carrying the condition has either a filled square or circle.

Sex chromosomes
Not enough information was provided.
The cause is environmental, not genetic.
Q. When the expression of one gene modifies the expression of a different gene, it is known as

Q. Which of the following statements about mutant alleles is incorrect?

Mutant alleles are rare alleles.
A mutant allele is always recessive.
A mutant allele causes a mutant phenotype.
A mutant allele does not necessarily result in a abnormal phenotype.
A mutant allele can be used in genetic studies.
Q. If a true breeding chinchilla rabbit is crossed with a true breeding Himalayan rabbit, all the offspring are chinchilla. What does this information tell you about the relationship between the chinchilla and Himalayan alleles?

Himalayan is dominant to chinchilla.
Himalayan is recessive to chinchilla.
Chinchilla and himalayan are codominant.
Chinchilla is incompletely dominant.
Not enough information is provided.
Q. If the phenotypic ratio of offspring from a cross between a Himalayan rabbit and a chinchilla rabbit is 2 chinchilla : 1 Himalayan: 1 albino, what were the genotypes of the parents?

cchcch × chch
cchc × chch
cchch × chc
cchc × chc
cchcch × chc