What is the mechanism of inheritance of this trait?
What is the mechanism of inheritance of this trait?
1. Having hair on the back of the hands is a dominant trait. If two people who heterozygous for the condition have children, what is the probability that they will have a child who does NOT have hair on the back of their hands?
0%  
25% or 1/4  
50% or 2/4  
75% or 3/4  
100% or 4/4 
8.5 points
QUESTION 2
1. Who is responsible for sex determination in humans?
male  
female 
6.5 points
QUESTION 3
1. In the pedigree below, all shaded individuals express the gene in question. For example, Arlene “has” the trait, she displays the phenotype in question. For example, if we were following the inheritance pattern of a widow’s peak, Arlene has a widow’s peak (that is NOT the trait here, just an example). Unshaded individuals (blank circles and squares) do not manifest the trait in question, but their specific genotype is unknown – they could be heterozygous, homozygous dominant, or homozygous recessive.
2. What is the mechanism of inheritance of this trait?
recessive  
dominant 
8.5 points
QUESTION 4
1. In the pedigree below, all shaded individuals express the gene in question. For example, Arlene “has” the trait, she displays the phenotype in question. For example, if we were following the inheritance pattern of a widow’s peak, Arlene has a widow’s peak (that is NOT the trait here, just an example). Unshaded individuals (blank circles and squares) do not manifest the trait in question, but their specific genotype is unknown – they could be heterozygous, homozygous dominant, or homozygous recessive.
What is Sam’s genotype?
homozygous recessive (hh)  
heterozygous (Hh)  
homozygous dominant (HH) 
8.5 points
QUESTION 5
1. Normally when a person consumes a product that contains lactose (such as milk or cheese), the body breaks the sugar lactose down into galactose and glucose. Galactosemia is disorder caused by a missing or defective enzyme which ends up causing galactose to accumulate to poisonous and sometimes deadly levels. Galactosemia is a recessive disorder. If two individuals are heterozygous for this trait, what is the probability that their children WILL HAVE galactosemia?
0%  
1/4 or 25%  
2/4 or 50%  
3/4 or 75%  
4/4 or 100% 
8.5 points
QUESTION 6
1. Huntington’s disease is characterized by a late onset of nerve degeneration that leads to death. The allele that causes the disease is dominant. Lucille is homozygous dominant for the disease and Joe is homozygous recessive. What is the probability that their children will have Huntington’s disease?
0%  
1/4 or 25%  
2/4 or 50%  
3/4 or 75%  
4/4 or 100% 
8.5 points
QUESTION 7
1. Hemophilia, disease in which the blood lacks a clotting factor, is caused by an X linked recessive gene. Joe doe not have hemophilia and Lucille is heterozygous for the condition. What is the chance that their MALE child will have hemophilia? (Note: you are calculating the probability for their MALE children only, in other words if they have 1 male child, what is the probability that he will be born with the disease?)
0%  
1/4 or 25%  
2/4 or 50%  
3/4 or 75%  
4/4 or 100% 
8.5 points
QUESTION 8
1. In humans, having facial dimples is dominant to not having facial dimples. Mary has dimples, yet only 3 of her 10 children have dimples. What must Mary’s genotype be?
homozygous dominant  
heterozygous  
homozygous recessive  
has dimples  
does not have dimples 
8.5 points
QUESTION 9
1. Redgreen color blindness is an Xlinked recessive disorder. If Allison is heterozygous (a carrier), and her husband, Michael, is NOT colorblind. What is the chance that their male children will be colorblind? (Note: you are calculating the probability for their MALE children only, in other words if they have 1 male child, what is the probability that he will be born with the disease?)
0%  
25% or 1/4  
50% or 2/4  
75% or 4/4  
100% or 4/4 
8.5 points
QUESTION 10
1. Redgreen color blindness is an Xlinked recessive disorder. If Allison is heterozygous (a carrier), and her husband, Michael, is NOT colorblind. What is the chance that their female children will be colorblind? (Note: you are calculating the probability for their FEMALE children only, in other words if they have 1 female child, what is the probability that she will be born colorblind?)
0%  
25% or 1/4  
50% or 2/4  
75% or 3/4  
100% or 4/4 
8.5 points
QUESTION 11
1. Match the term to its best description.


QUESTION 12
1. Why do Xlinked genetic disorders occur more frequently in males? Answer in a few short sentences.