Jakob_PS1 - Problem
Set
1
 
 1.

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Unformatted text preview: Problem
Set
1
 
 1. What
two
important
changes
take
place
at
the
level
of
the
DNA
during
meiosis?
 
 2. What
is
“criss‐cross”
inheritance
and
what
is
it
often
associated
with?
 3. A
boy
is
born
with
protanopia
(X‐linked),
although
both
of
his
parents
have
normal
 color
perception.
On
his
maternal
side,
he
has
two
aunts
and
six
uncles.
Two
of
his
 maternal
uncles
but
none
of
his
maternal
aunts
have
protanopia.
(Fairbanks
&
 Andersen.
Chapter
14,
Q:
#18)
 
 a. Which
of
his
maternal
grandparents
carried
the
protanopia
allele?
 
 b. Did
either
of
his
maternal
grandparents
have
protanopia?

 
 4. In
humans,
all
the
male
children
of
mothers
who
have
G6PD
deficiency
also
have
the
 trait.
(G6PD
deficiency
is
a
benign
condition
that
can
cause
anemia
upon
exposure
to
 certain
substances.)
Rarely,
a
father
with
G6PD
deficiency
also
has
a
son
with
the
 trait.
(Fairbanks
&
Andersen.
Chapter
14,
Q:
#21)
 a. What
is
the
most
likely
genetic
basis
for
G6PD
deficiency?
 
 b. How
can
the
rare
occurrence
of
sons
with
G6PD
deficiency
whose
father
also
 had
the
trait
best
be
explained?
 MCB
104
–
Section
105/106
 
 
 
 5. R.A.
Emerson
crossed
two
different
pure‐breeding
lines
of
corn
and
obtained
a
 phenotypically
wild‐type
F1
that
was
heterozygous
for
three
alleles
that
determine
 recessive
phenotypes:
an
determines
anther;
br,
brachytic;
and
f,
fine.
He
 testcrossed
the
F1
with
a
tester
that
was
homozygous
recessive
for
the
three
genes
 and
obtained
these
progeny
phenotypes:
355
anther;
339
brachytic,
fine;
88
 completely
wild
type;
55
anther,
brachytic,
fine;
21
fine;
17
anther,
brachytic;
2
 brachytic;
2
anther,
fine.
(Chapter
4,
Q:
#12)
 
 
 
 
 
 
 
 
 
 a. What
were
the
genotypes
of
the
parental
lines?
 b. Draw
a
linkage
map
for
the
three
genes
(include
map
distances).
 c. Calculate
the
interference
value.
 
 
 
 6. An
individual
heterozygous
for
four
genes,
A/a
•
B/b
•
C/c
•
D/d,
is
testcrossed
with
 a/a
•
b/b
•
c/c
•
d/d,
and
1000
progeny
are
classified
by
the
gametic
contribution
of
 the
heterozygous
parent
as
follows.
(Chapter
4,
Q:
#45)
 
 a
•
B
•
C
•
D
 
 42
 A
•
b
•
c
•
d
 
 43
 A
•
B
•
C
•
d
 
 140
 a
•
b
•
c
•
D
 
 145
 a
•
B
•
c
•
D
 
 6
 A
•
b
•
C
•
d
 
 9
 A
•
B
•
c
•
d
 
 305
 a
•
b
•
C
•
D
 
 310
 
 a. Which
genes
are
linked?
 
 b. If
two
pure‐breeding
lines
had
been
crossed
to
produce
the
heterozygous
 individual,
what
would
their
genotypes
have
been?
 c. Draw
a
linkage
map
of
the
linked
genes,
showing
the
order
and
the
 distances
in
map
units.
 d. Calculate
interference
value(s),
if
appropriate
 7. A
team
of
researchers
recently
discovered
a
new
disease
they
named
unicornism.
In
 one
family,
three
of
six
siblings
had
discovered
a
horn
growing
from
their
forehead
 on
the
morning
of
their
50th
birthday.
Because
their
parents
had
both
died
before
 they
turned
50,
this
family
did
not
know
if
the
parents
were
afflicted
with
the
 disease.
Luckily
doctors
were
able
to
retrieve
parental
DNA
from
frozen
tissue
 samples.
Hoping
to
map
the
unicornism
gene,
the
researchers
designed
two
sets
of
 PCR
primers
to
amplify
two
microsatellites.
The
DNA
gel
from
this
PCR
is
shown
 below.
 
 a. Which
microsatellite
is
most
likely
linked
to
the
gene
for
unicornism?
 
 
 
 
 
 
 
 
 
 
 b. Which
parent
would
have
been
afflicted
with
unicornism
on
their
50th
 birthday?
What
must
the
genotype
of
this
parent
have
been
with
respect
to
 the
unicornism
gene?
 
 
 
 
 ?
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