Download Evaluating Mendelian and Non

Biology
HS/Science
Unit: 08 Lesson: 02
Evaluating Mendelian and Non-Mendelian Crosses PI KEY
Use the following key to complete problems 1–5. Show all work using Punnett squares, AND
summarize your answers below that work.
Key
This key provides you with information about certain genetic traits in monsters.
T – No tail
t – Tail present
B – Blue fur
b – Yellow fur
H – Small head
h – Large head
**The blue fur allele is not completely dominant over yellow fur.
Because of this, heterozygotes have green fur.
G – Green tongue
R – Red tongue
O – Orange tongue
**The green and red tongue color alleles are codominant.
This means that monsters that have both the green tongue
allele and red tongue allele, have tongues with green and
red spots. The allele for orange color is recessive.
XA – Ability to see in the dark
Xa – Cannot see in the dark
**The alleles for eye sight are sex-linked because
they are found only on the X chromosome.
1. A cross is made between two monsters in the F1 generation. The parents of the F1
generation were homozygous small headed and homozygous large headed.
H
h
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H
Hh
Hh
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Biology
HS/Science
Unit: 08 Lesson: 02
Hh
h
Hh
What are the phenotypic and genotypic ratios of the F2 generation? 4:4 are all smallheaded (100%). 4:4 are Hh (100%) heterozygous.
If these F1 monsters had 100 offspring in the F2 generation, predict how many would have
the same phenotype as their parents. Approximately 100 of the offspring would have the
same phenotype as one parent (small-headed).
2. A dihybrid cross is made between two heterozygote monsters with small heads and no
tails.
What are the phenotypic and genotypic ratios of the F1 generation?
Phenotypic ratios: 9 small-headed and no tail: 3 small-headed and tail: 3 large-headed and
no tail: 1 large-headed and tail
Genotypic ratios: 1 HHTT: 2 HHTt: 2 HhTT: 4 HhTt: 1 HHtt: 2 Hhtt: 1 hhTT: 2 hhTt: 1 hhtt
What percentage of F1 offspring do you predict have the same genotype as their parents?
Approximately 56.25% (9/16) will have the same genotype as their parents (small
heads and no tails).
HT
HT
Ht
hT
ht
HHTT
HHTt
HhTT
HhTt
HHTt
HHtt
HhTt
Hhtt
HhTT
HhTt
hhTT
hhTt
HhTt
Hhtt
hhTt
hhtt
Ht
hT
ht
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Biology
HS/Science
Unit: 08 Lesson: 02
3. A female monster that cannot see in the dark is crossed with a male monster that can.
What are the phenotypic and genotypic ratios of the F1 generation?
Phenotypic ratios: 1 XAXa: 1 XaY
Genotypic ratios: 1 female can see in the dark: 1 male can’t see in the dark
What percentage of F1 offspring will be females that can see in the dark?
50% of the F1 offspring will be females that can see in the dark.
Xa
XA
Y
Xa
XAXa
XaY
XAXa
XaY
4. A cross is made between a monster with an orange tongue and a monster with a red and
green spotted tongue.
What are the phenotypic and genotypic ratios of the F1 generation?
Phenotypic ratio: 1 green tongue: 1 red tongue
Genotypic ratio: 1 GO: 1 RO
What percentage of the offspring will have a different looking tongue from their parents?
100% of the offspring will have a different looking tongue from their parents. The
offspring will have either green or red tongue, no orange and no green and red
spotted.
O
©2012, TESCCC
O
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Biology
HS/Science
Unit: 08 Lesson: 02
G
R
GO
GO
RO
RO
5. Two monsters with green fur are crossed.
What are the phenotypic and genotypic ratios of the F1 generation?
Phenotypic ratio: 1 blue: 2 green: 1 yellow
Genotypic ratio: 1BB: 2Bb: 1bb
What percentage of the offspring will have a different phenotype than their parents?
50% of the offspring will have a phenotype different than their parents, 25% blue and 25%
yellow.
B
B
b
©2012, TESCCC
b
BB
Bb
Bb
bb
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