Bio 211 Materials
|
Bio 211 Materials |
Exercise
II-19
Genetics
Problem Set
1. In summer squashes, white fruit is dominant
to yellow fruit. The allele that codes
for white fruit is represented by W and the allele that codes for yellow fruit
by w. What are the genotypes of all
possible gametes produced by plants with the following genotypes?
A. WW
B. Ww
C. ww
2. Do Punnett squares for the following crosses
and give the fruit color for the offspring.
A. Ww
X ww
B. WW
X Ww
C. WW X ww
3.
Hemophilia in humans is due to a sex-linked recessive gene, h. A normal woman
with no history of hemophilia in her family marries a normal man who had a
hemophilic father. What percentage
of their children will have hemophilia?
4.
Use the same information in question #1 but change the man to having a hemophilic
mother.
5.
Normal vision (C) in humans is dominant to color blindness © and is sex-linked. A normal-visioned man, whose father was colorblind,
marries a colorblind woman. What are
the chances that a son will be colorblind?
What are the
chances that a daughter will be colorblind?
6.
The determiner for brown eyes (B) is dominant to blue eyes (b) and is not
sex linked. A colorblind man with brown eyes, whose mother
was blue-eyed, marries a normal-visioned, blue-eyed woman, whose father was
colorblind. Show the expected phenotype
ratio of their children involving eye color and color blindness.
7. Blood types in humans are caused by a combination
of two of three possible alleles IA, IB and i.
The i allele is recessive and when an individual is homozygous for
this allele, they have type O blood. Blood type A may be due to a homozygous condition
(IA, IA ) or the heterozygous genotype (IA , i). Blood type AB is caused by having a copy of
both the IA and IB alleles. Rh factor is another marker on human red blood cells and is either
positive (dominant R) or negative
(recessive r). Give all possible genotypes
for each blood type regarding IA, IB and i alleles.
A. A man that has blood type A
negative, whose father was B positive and whose mother was AB positive, married
a woman that was B positive. The
woman’s mother was A negative and her father was AB positive. Give the genotypes of all the above
mentioned individuals.
B. Give the genotypes and phenotypes of the possible offspring from this
marriage.
8.
In humans, brown eyes (B) are considered to be dominant to blue eyes (b). A brown-eyed man marries a blue-eyed woman
and they have eight children, all brown eyed.
Accepting the hypothesis that a single gene codes for eye color, what
would be the genotypes of each individual in this family?
9. A blue-eyed man, whose parents were brown-eyed,
marries a brown-eyed woman whose father was brown-eyed and whose mother was
blue-eyed. They have one child, who
is blue-eyed. Assuming these traits
are controlled by a single pair of alleles, B and b as in #6, what are the
genotypes of all the individuals?
10. In incomplete dominance the
heterozygous condition results in some intermediate trait.
In humans, curly hair is homozygous dominant and straight hair is homozygous
recessive. The heterozygous individual
will have wavy hair. Using the alleles C and c give the genotypes for each
of the above three phenotypes. If
a father has wavy hair and the mother has wavy hair give the percentage of
the offspring with each genotype and phenotype.