Transcript Dihybrid crosses: Making Monsters

TWO FACTOR CROSSES: MONSTERS INC.


First Generation– A pure squareheaded round-eyed monster
is crossed with a pure
triangular-headed oval-eyed
(hybrid) monster.
Triangular head and oval
eyes are both dominant
traits.
MAKING MONSTERS
a.
b.
c.
d.


What is the symbol for the triangular-headed
T
trait?___
t
Square-headed trait?___
O
What is the symbol for the oval-eyed trait? ___
o
Round-eyed trait?___
ttoo
Genotype:_________
Pure through and through
Genotype:___________
TTOo
Pure and hybrid
CONSTRUCTING THE PUNNETT SQUARE
c) First figure out the possible allele
combinations each monster can produce for its
gametes!
ttoo: to
TTOo: TO and To
NOW DRAW THE PUNNETT SQUARE
Possible
Gametes
TO
To
to
TtOo
Ttoo
to
TtOo
Ttoo
BABY MONSTERS
d) Draw pictures of the types of monsters that
result from the cross 
TtOo
Genotype:_______
Genotype:________
Ttoo
e) Now, construct a Punnett Square of a
cross showing the possible offspring from
these two monsters. But first 
CONSTRUCTING THE PUNNETT SUARE
f)
g)
h)
Begin by figuring out the possible allele
combinations each monster can produce for
its gametes!
TtOo: TO, To, tO, to
Ttoo: To, to
NOW DRAW THE PUNNETT SQUARE
TO
To
tO
to
To
TTOo Ttoo TtOo Ttoo
to
TtOo Ttoo ttOo ttoo
WHAT TYPES OF MONSTERS WERE MADE?
HOW MANY OF EACH?
1 Square head/round eyes
3 Triangular Head/oval eyes
1 Square head/oval eyes
3 Triangular head/round eyes