Download I- ln cats, the genotype BB is black, Bb is calico (ortortoise shell), and

SEX-LTNKED TNHERTTANCE
I-
ln cats, the genotype BB is black, Bb is calico (ortortoise shell), and bb is yellow. The gene is
on the X chroinosome (and ir.obviously codominant). A.calico female is crossed with a black
male. What offspring would be expected? Would you expect to find any calico males?
whv?
2- ln humans, color bllndness is due to a sex-linked recessive, while blue eyes are due to an
.
autosomal recessive. Two brown-eyed parents with normal vision produce a blue-eyed
colorblind son. What are the genotypes of the parents?
3- A blue-eyed woman
whose father was colorblind marries a brown-eyed man whose mother
was blue-eyed. What proportions of their sons would be blue-eyed and colorblind?
4.
A normal visioned woman takes her daughter to an ophthalmologist for an examination. The
doctor finds that the girl is colorblind. What does the doctor know about her father? What
does she know about her mother?
5- ln humans, hemophilia A, the "bleeders disease" in which the time required
for blood to clot
greatly prolonged, depends upon the recessive allele of a sex-linked gene. ln the fbllowing
questions, let X = normal clotting ti.me and Xh : the allele for hemophilia.
is
a. A man ',vhose father
.
:.
b.
c.
5.
was hemophilic, but whose own blood clotting time is normal,
marries a normal woman with no record of hemophilia in her ancestry. What are the
chances of hemophilia in their children?
A woman whose father was hemophilic, but whose own blood clotting time is normal,
marries a normal man. What are the chances of hemophilia in their children?
What is the chance of hemophilia among the sons of a dar.rghter of the marriage in the
previous question if she marries a normal man? (l love that sentencel). lf she marries a
hemophiliac?
A tortoise shell cat (calico) has a litter of eight kittens: one yellow male, two black males., two
yellow females, and three calico females. Assuming there is a single father for the lit[er, what
is his probable color?
7. That reminds
me - did you hear about the cat who swallowed a ball of yarn?
She had mittensl
8. A black cat has a lit[er of seven kiftens: three black males, one black female and three calico
females. Comment on the probable paternity of this litter.
9. A yellow cat has a litter of four kittens:
father for the litter, what
one yellow and three calico. Assuming there
yellow
kitten?
is the sex of the
is one
'
for non-rolling' The gene for
The gene for rolling your tongue is iominant to the.gene
and is sex-linked- The Rh+ factor in
hemophiria is recessive to the gene for normar brood crotting
the blood is dominant to the Rh- faclor
and Rh- blood' His sister Tillie
Little lonny TifFenbroom cannot rolr his tongue, has hemophilia
has Rh- blood'
can roll her tongue, does not have hemophilia' and
not have hemophilia and has Rh+
Jonny and Tillie's father, Tyrone, can roll his tongue' does
of course she has normal blood
blood. Mrs. Tiffenbroom (Magnolia) cannot roll her tongfue,
and has Rh+ blood'
clotting (or she would have died in .iifOUirth or before),
What are the genotypes of Jonny's parents?
chird will be a boy who can roii
the probabirity that Tyrone and Magnoria's next
tongue, has normal blood clotting and Rh+ blood?
what
his
is
Actuallv,Mr.andMrs.Tifienbroom'snextchildwasagirl'whatisth.eprobabilitythatthisgirl
blood clotting and Rh- blood?
not be able to roll her tongue; would have normal
.would