Bil 150 Practice Genetics
Problems: ( ? = answers )
1. In squash the gene, W for
white color, is dominant over its allele, w for yellow color.
The expected F1 phenotype(s) from a cross
between homozygous white
and homozygous yellow squash would
be ?
2.
In ALF's
(Alien Life Forms) brown fur (B) is dominant to white fur (b).
A brown
furred ALF named Charly is crossed
with a white furred ALF
and the progeny occur in the ratio of 50% brown to 50%
white.
What is the likely genotype of Charly ?
3. Charly in the
above question has a genotype that is
?
a)
homozygous dominant
b) homozygous recessive
c) heterozygous
d)
dihybrid
e) unknown
4. The ability to roll one's tongue into a U-shape is
believed to be determined
by the presence of a non-sex linked
dominant gene, T.
A man, unable to roll his tongue, and a woman able to
roll hers, have four
children. The woman's mother couldn't
roll her tongue, but her father could.
Of their four children how many might
you expect to unable to roll their tongues ?
5. A human recessive genetic
disease, termed Charlyitis, is
found on chromosome 12
and is often fatal.
Suppose by chance that a boy, Michael, who has this
disease
lives past puberty and
marries a normal woman, but whose father also had
Charlyitis.
If this couple have any
children what is the probability that the children
will
have Charlyitis
?
6.
College World Series Omaha-itis is a
sex-linked recessive disease
of the species
Ibis, which is
quite often fatal. Death, however, occurs
only in the years of
National Championships. It has been determined that,
by chance, Sebastian
(the Hurricane Ibis male mascot)
has the disease
and mates with
a female Ibis
who is heterozygous for the disease.
A) if
they have a single chick, what is the probability that it
will have the disease,
and B)
if Sebastian and his bride have a male
chick, what is the probability
that he would have the disease ?
7. A couple has four children
whose blood types are A, B, and AB.
Which of the following genotypes is
capable of producing the blood types
of this couples children ?
a) Ai and Bi
b) Ai and
BB
c) Ai and
ii
d) Bi and
ii
