1. Which of the following statements is correct?
Dominance and recessiveness are not linked to the sex chromosomes.
Mendels label of unit factors are what we now refer to as genes.
2. True or False: A dominant gene will always cause the expression of a
dominant phenotype in any genetic cross.
False
3. People with sickle-cell disease can become very sick under what
conditions?
High altitudes
4. A homozygous long-haired cat is bred to a homozygous short-haired
cat. Assuming that the gene for long hair is completely dominant,
what are the chances of the F1 offspring being long-haired?
100%
5. A dog breeder is looking to cross a long-haired female dog with a
short-haired male dog. The gene for hair length has incomplete
dominance. By crossing the F1 offspring, what percentage of the F2
generation are predicted to be short-haired?
A 1:2:1 ratio predicts 25% of the offspring to be homozygous short-
haired.
6. Consider 3 genes that assort independently in squirrels. A gene for
brown color is dominant (D), a gene for a bushy tail is dominant
(B), and a gene for reflux after eating acorns is recessive (a). Use the
product law to predict the likelihood of producing a squirrel (from
parents that are heterozygous for each trait individually) that is
brown, bushy-tailed, and has reflux from all those acorns.
(3/4) x (3/4) x (1/4) = 9/64 probability of this squirrel being
brown, bushy-tailed, and having reflux.
7. Two individuals with widow's peaks have a child with a straight
hairline.
A. Is the gene for a widow's peak likely dominant or recessive?
B. Could you predict the genotype of the parents, assuming there is no
codominance?
C. If the child with the straight hairline someday marries a person
, with a widow's peak, can you predict for certain whether their
offspring will have a widow's peak?
Dominance and recessiveness are not linked to the sex chromosomes.
Mendels label of unit factors are what we now refer to as genes.
2. True or False: A dominant gene will always cause the expression of a
dominant phenotype in any genetic cross.
False
3. People with sickle-cell disease can become very sick under what
conditions?
High altitudes
4. A homozygous long-haired cat is bred to a homozygous short-haired
cat. Assuming that the gene for long hair is completely dominant,
what are the chances of the F1 offspring being long-haired?
100%
5. A dog breeder is looking to cross a long-haired female dog with a
short-haired male dog. The gene for hair length has incomplete
dominance. By crossing the F1 offspring, what percentage of the F2
generation are predicted to be short-haired?
A 1:2:1 ratio predicts 25% of the offspring to be homozygous short-
haired.
6. Consider 3 genes that assort independently in squirrels. A gene for
brown color is dominant (D), a gene for a bushy tail is dominant
(B), and a gene for reflux after eating acorns is recessive (a). Use the
product law to predict the likelihood of producing a squirrel (from
parents that are heterozygous for each trait individually) that is
brown, bushy-tailed, and has reflux from all those acorns.
(3/4) x (3/4) x (1/4) = 9/64 probability of this squirrel being
brown, bushy-tailed, and having reflux.
7. Two individuals with widow's peaks have a child with a straight
hairline.
A. Is the gene for a widow's peak likely dominant or recessive?
B. Could you predict the genotype of the parents, assuming there is no
codominance?
C. If the child with the straight hairline someday marries a person
, with a widow's peak, can you predict for certain whether their
offspring will have a widow's peak?
