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Figure 11.1
© 2014 Pearson Education, Inc.
Mendelian Genetics
Figure 11.5-3
P Generation
Purple flowers White flowers
Appearance:
PP
pp
Genetic makeup:
p
P
Gametes:
F1 Generation
Appearance:
Genetic makeup:
Gametes:
Purple flowers
Pp
½ p
½ P
Sperm from
F1 (Pp) plant
F2 Generation
P
p
PP
Pp
Pp
pp
P
Eggs from
F1 (Pp) plant
p
3
© 2014 Pearson Education, Inc.
:1
Figure 11.6
3
Phenotype
Genotype
Purple
PP
(homozygous)
Purple
Pp
(heterozygous)
1
2
1
© 2014 Pearson Education, Inc.
Purple
Pp
(heterozygous)
White
pp
(homozygous)
Ratio 3:1
Ratio 1:2:1
1
Table 11.1
© 2014 Pearson Education, Inc.
Figure 11.8
Experiment
YYRR
P Generation
yyrr
Gametes YR
yr
F1 Generation
YyRr
Hypothesis of
dependent assortment
Predictions
Hypothesis of
independent assortment
Sperm
or
Predicted
offspring in
F2 generation
¼ YR ¼ Yr ¼ yR ¼ yr
Sperm
½ YR ½ yr
¼ YR
½ YR
Eggs
½ yr
YYRR YyRr
YyRr
¾
yyrr
¼ Yr
Eggs
¼ yR
YYRR YYRr
YyRR YyRr
YYRr
YYrr
YyRr
Yyrr
YyRR YyRr
yyRR
yyRr
YyRr
yyRr
yyrr
¼
Phenotypic ratio 3:1
¼ yr
9
16
3
16
Yyrr
3
16
1
16
Phenotypic ratio 9:3:3:1
Results
315
© 2014 Pearson Education, Inc.
108
101
32
Phenotypic ratio approximately 9:3:3:1
Figure 11.4
Allele for purple flowers
Locus for flower-color gene
Pair of
homologous
chromosomes
Allele for white flowers
© 2014 Pearson Education, Inc.
Figure 11.9

Rr
Segregation of
alleles into eggs
Rr
Segregation of
alleles into sperm
Sperm
R
½
R
R
½
¼
¼
r
r
r
R
r
¼
© 2014 Pearson Education, Inc.
r
R
R
Eggs
½
r
½
¼
Multiplication Rule: The probability that two or
more events will occur together is the product
of the individual probabilities
Addition Rule: the probability that any one of
two mutually exclusive events will occur is
calculated by adding together their individual
probabilities.
© 2014 Pearson Education, Inc.
Figure 11.10-3
P Generation
Red
CRCR
White
CWCW
Gametes
CR
CW
Pink
CRCW
F1 Generation
Gametes ½ CR ½ CW
Sperm
½ CR ½ CW
F2 Generation
½ CR
Eggs
CRCR
CRCW
CRCW
CWCW
½ CW
© 2014 Pearson Education, Inc.
Figure 11.11
(a) The three alleles for the ABO blood groups and their
carbohydrates
Allele
Carbohydrate
IB
IA
i
none
B
A
(b) Blood group genotypes and phenotypes
Genotype
IAIA or IAi
IBIB or IBi
IAIB
ii
A
B
AB
O
Red blood cell
appearance
Phenotype
(blood group)
© 2014 Pearson Education, Inc.
Figure 11.14b
Key
Male
Female
Affected
male
Offspring, in
birth order
(first-born on left)
Affected
female
1st generation
(grandparents)
2nd generation
(parents, aunts,
and uncles)
Mating
Ff
FF or
Ff
ff
Ff
ff
ff
Ff
Ff
Ff
ff
ff
FF
or
Ff
3rd generation
(two sisters)
Attached earlobe
Free earlobe
(b) Is an attached earlobe a dominant or recessive trait?
© 2014 Pearson Education, Inc.
Figure 11.16
Parents
Dwarf
Dd
Normal
dd
Sperm
D
d
d
Dd
Dwarf
dd
Normal
d
Dd
Dwarf
dd
Normal
Eggs
© 2014 Pearson Education, Inc.
12
The Chromosomal
Basis of Inheritance
© 2014 Pearson Education, Inc.
Figure 12.1
© 2014 Pearson Education, Inc.
Figure 12.2
P Generation
Yellow-round
seeds (YYRR)
Green-wrinkled
seeds (yyrr)
Y
R
Y
r
R
y
r
y
Meiosis
Fertilization
Gametes
r
y
R Y
All F1 plants produce
yellow-round seeds (YyRr).
F1 Generation
R
R
y
r
y
r
Y
Y
Meiosis
LAW OF SEGREGATION
The two alleles for each
gene separate.
R
r
Y
y
r
R
Y
y
Metaphase
I
LAW OF INDEPENDENT
ASSORTMENT Alleles of
genes on nonhomologous
chromosomes assort
independently.
1
1
R
r
Y
y
r
R
Y
y
Anaphase I
R
r
Y
y
Metaphase
II
r
R
Y
y
2
2
R
R
/4
1
YR
F2 Generation
3 Fertilization
recombines the R and
r alleles at random.
© 2014 Pearson Education, Inc.
y
Y
Y
r
r
r
/4
1
yr
Y
Y
y
YR
r
/4
1
Yr
An F1  F1 cross-fertilization
9
:3
:3
:1
y
y
R
R
/4
1
yR
3 Fertilization results in the
9:3:3:1 phenotypic ratio
in the F2 generation.
Figure 12.2a
P Generation
Yellow-round
seeds (YYRR)
Green-wrinkled
seeds (yyrr)
Y
Y
r
R R
y
y
r
Meiosis
Fertilization
Gametes
© 2014 Pearson Education, Inc.
R Y
y
r
Figure 12.2b
F1 Generation
R
All F1 plants produce
yellow-round seeds (YyRr).
R
y
r
y
r
Y
Y
LAW OF INDEPENDENT
ASSORTMENT
Alleles of genes on
nonhomologous
chromosomes assort
independently.
Meiosis
LAW OF
SEGREGATION
The two alleles for
each gene separate.
R
r
Y
y
r
R
Y
y
Metaphase
I
1
1
R
r
r
R
Y
y
Anaphase I
Y
y
r
R
Metaphase
II
R
r
2
2
y
Y
Y
R
R

14
YR
© 2014 Pearson Education, Inc.
r

14
yr
Y
Y
y
r
y
Y
y
Y
r
r

14
Yr
y
y
R
R

14
yR
Figure 12.2c
LAW OF
SEGREGATION
LAW OF
INDEPENDENT
ASSORTMENT
F2 Generation
3 Fertilization
An F1  F1 cross-fertilization 3 Fertilization results
in the 9:3:3:1
recombines the
phenotypic ratio in
R and r alleles
9
:3
:3
:1
the F2 generation.
at random.
© 2014 Pearson Education, Inc.
Figure 12.4
Experiment
P
Generation
F1
Generation
Conclusion
P
Generation
X
X
w
w
All offspring
had red eyes.
w
Eggs
Results
F2
Generation
X
Y
F1
Generation
w
Sperm
w
w
w
w
Eggs
F2
Generation
w
w
Sperm
w
w
w
w
w
w
© 2014 Pearson Education, Inc.
w
Figure 12.4a
Experiment
P
Generation
F1
Generation
Results
F2
Generation
© 2014 Pearson Education, Inc.
All offspring
had red eyes.
Figure 12.4b
Conclusion
P
Generation
X
X
w
X
Y
w
w
Eggs
F1
Generation
Sperm
w
w
w
w
w
Eggs
F2
Generation
w
w
Sperm
w
w
w
w
w
w
© 2014 Pearson Education, Inc.
w
Figure 12.5
X
Y
© 2014 Pearson Education, Inc.
Figure 12.6
44 
XY
Parents
22 
X
22 
22 
or Y
X
Sperm
44 
XX
44 
XX
Egg
or
44 
XY
Zygotes (offspring)
© 2014 Pearson Education, Inc.
Figure 12.7
X NX N
Xn
XN
Sperm
Y
Eggs XN
X NX n X NY
XN
X NX n X NY
(a)
X NX n
XnY
X NX n
X NY
Y
Sperm
Xn
XnY
Y
Eggs XN
X NX N X NY
Eggs XN
XNXn XNY
Xn
XNXn XnY
Xn
XnXn XnY
(b)
© 2014 Pearson Education, Inc.
(c)
Sperm
Figure 12.8
X chromosomes
Early embryo:
Two cell
populations
in adult cat:
Allele for
black fur
Cell division and
X chromosome
inactivation
Active X
Inactive
X
Active X
Black fur
© 2014 Pearson Education, Inc.
Allele for
orange fur
Orange fur
Figure 12.8a
© 2014 Pearson Education, Inc.
Figure 12.UN01
F1 dihybrid female
and homozygous
recessive male
in testcross
b vg
b vg
b vg
b vg
b vg
b vg
Most offspring
or
b vg
© 2014 Pearson Education, Inc.
b vg
Figure 12.9
Experiment
P Generation
(homozygous)
Wild type
(gray body,
normal wings)
Double mutant
(black body,
vestigial wings)
b b vg vg
b b vg vg
F1 dihybrid testcross
Homozygous
recessive (black
body, vestigial
wings)
Wild-type F1 dihybrid
(gray body, normal wings)
b b vg vg
b b vg vg
Testcross
offspring
b vg
b vg
b vg
Wild-type
(gray-normal)
Blackvestigial
Grayvestigial
Blacknormal
b b vg vg
b b vg vg
Eggs b vg
b vg
Sperm
b b vg vg b b vg vg
PREDICTED RATIOS
Genes on different
chromosomes:
1
:
1
:
1
:
1
Genes on some
chromosome:
1
:
1
:
0
:
0
965
:
944
:
206
:
185
Results
© 2014 Pearson Education, Inc.
Figure 12.9a
Experiment
P Generation
(homozygous)
Wild type
(gray body,
normal wings)
Double mutant
(black body,
vestigial wings)
b b vg vg
b b vg vg
F1 dihybrid testcross
Wild-type F1 dihybrid
(gray body, normal wings)
b b vg vg
© 2014 Pearson Education, Inc.
Homozygous
recessive (black
body, vestigial
wings)
b b vg vg
Figure 12.9b
Experiment
Testcross
offspring
Eggs b vg
b vg
b vg
b vg
Grayvestigial
Wild-type
Black(gray-normal) vestigial
Blacknormal
b vg
Sperm
b b vg vg
b b vg vg
b b vg vg b b vg vg
PREDICTED RATIOS
Genes on different
chromosomes:
1
:
1
:
1
:
1
Genes on same
chromosome:
1
:
1
:
0
:
0
965
:
944
:
206
:
185
Results
© 2014 Pearson Education, Inc.
Figure 12.UN02
Gametes from yellow-round
dihybrid parent (YyRr)
Gametes from greenwrinkled homozygous
recessive parent (yyrr)
YR
yr
Yr
yR
YyRr
yyrr
Yyrr
yyRr
yr
Parentaltype
offspring
© 2014 Pearson Education, Inc.
Recombinant
offspring
Recombination of Linked Genes:
Crossing Over
• Morgan discovered that even when two genes
were on the same chromosome, some recombinant
phenotypes were observed
• He proposed that some process must occasionally
break the physical connection between genes on
the same chromosome
• That mechanism was the crossing over between
homologous chromosomes
Animation: Crossing Over
© 2014 Pearson Education, Inc.
Figure 12.10
P generation
(homozygous)
Wild type (gray body,
normal wings)
F1 dihybrid testcross
Double mutant (black body,
vestigial wings)
b vg+
b vg
b vg+
b vg
Wild-type F1 dihybrid
(gray body, normal wings)
Homozygous recessive
(black body, vestigial wings)
b vg+
b vg
b vg
b vg
Replication
of chromosomes
Meiosis I
Replication
of chromosomes
b vg+
b vg
b vg+
b vg
b vg
b vg
b vg
b vg
b vg+
Meiosis I and II
b vg
b vg
b vg
Meiosis II
b vg+
b vg
b vg
944
Blackvestigial
206
Grayvestigial
Eggs
Testcross
offspring
965
Wild type
(gray-normal)
b vg
185
Blacknormal
b vg
b vg
b vg
b vg
b vg
b vg
b vg
b vg
Parental-type offspring
Recombination

frequency
© 2014 Pearson Education, Inc.
Recombinant
chromosomes
Recombinant offspring
391 recombinants
2,300 total offspring
 100  17%
b vg
Sperm
Figure 12.10a
P generation (homozygous)
Wild type
(gray body,
normal wings)
Double mutant
(black body,
vestigial wings)
b vg+
b vg
b vg+
b vg
Wild-type F1 dihybrid
(gray body,
normal wings)
b vg+
b vg
© 2014 Pearson Education, Inc.
Figure 12.10b
F1 dihybrid testcross
Wild-type F1
dihybrid
(gray body,
normal wings)
b vg+
b vg
b vg
Meiosis I
b vg
b vg+
b vg
b vg+
b vg
b vg
b vg
b vg
b vg
Homozygous
recessive
(black body,
vestigial wings)
b vg+
Meiosis I and II
b
vg
b vg
b vg
Meiosis II
Eggs
b+ vg+
© 2014 Pearson Education, Inc.
b vg
Recombinant
chromosomes
b+ vg
b vg+
b vg
Sperm
Figure 12.10c
Recombinant
chromosomes
b vg+
b vg
b vg
944
Blackvestigial
206
Grayvestigial
b vg
Eggs
Testcross
offspring
965
Wild type
(gray-normal)
185
Blacknormal
b vg
b vg
b vg
b vg
b vg
b vg
b vg
b vg
Parental-type offspring
Recombinant offspring
Recombination
391 recombinants  100  17%

frequency
2,300 total offspring
© 2014 Pearson Education, Inc.
b vg
Sperm
Figure 12.11
Results
Recombination
frequencies
9%
Chromosome
17%
b
© 2014 Pearson Education, Inc.
9.5%
cn
vg
Figure 12.12
Mutant phenotypes
Short
aristae
0
Long aristae
(appendages
on head)
Black
body
Cinnabar
eyes
48.5 57.5
Gray
body
Red
eyes
Vestigial
wings
67.0
Normal
wings
Wild-type phenotypes
© 2014 Pearson Education, Inc.
Brown
eyes
104.5
Red
eyes
Figure 12.13-1
Meiosis I
Nondisjunction
© 2014 Pearson Education, Inc.
Figure 12.13-2
Meiosis I
Nondisjunction
Meiosis II
Nondisjunction
© 2014 Pearson Education, Inc.
Figure 12.13-3
Meiosis I
Nondisjunction
Meiosis II
Nondisjunction
Gametes
n1
n1
n−1
n−1
n1
n−1
n
n
Number of chromosomes
(a) Nondisjunction of homologous chromosomes in
meiosis I
© 2014 Pearson Education, Inc.
(b) Nondisjunction of sister
chromatids in meiosis II
Figure 12.14
(a) Deletion
(c) Inversion
A deletion removes a
chromosomal segment.
(b) Duplication
An inversion reverses a segment
within a chromosome.
(d) Translocation
A duplication repeats
a segment.
© 2014 Pearson Education, Inc.
A translocation moves a segment
from one chromosome to a
nonhomologous chromosome.
Figure 12.14a
(a) Deletion
A deletion removes a
chromosomal segment.
(b) Duplication
A duplication repeats
a segment.
© 2014 Pearson Education, Inc.
Figure 12.14b
(c) Inversion
An inversion reverses a segment
within a chromosome.
(d) Translocation
A translocation moves a segment
from one chromosome to a
nonhomologous chromosome.
© 2014 Pearson Education, Inc.
Figure 12.15
© 2014 Pearson Education, Inc.
Figure 12.15a
© 2014 Pearson Education, Inc.
Figure 12.15b
© 2014 Pearson Education, Inc.
Figure 12.16
Normal chromosome 9
Normal chromosome 22
Reciprocal translocation
Translocated chromosome 9
Translocated chromosome 22
(Philadelphia chromosome)
© 2014 Pearson Education, Inc.
Figure 12.UN03a
© 2014 Pearson Education, Inc.
Figure 12.UN03b
© 2014 Pearson Education, Inc.
Figure 12.UN04
Sperm
P generation
gametes
D
C
B
A
d
E
F
D
e
C
B
A
F
© 2014 Pearson Education, Inc.
Egg
e
f
This F1 cell has 2n  6 chromosomes and is heterozygous
for all six genes shown
(AaBbCcDdEeFf).
Red  maternal; blue  paternal.
Each chromosome has
hundreds or thousands
of genes. Four (A, B, C,
F) are shown on this one.
c
b
a
The alleles of unlinked
genes are either on
separate chromosomes
(such as d and e)
or so far apart on the
same chromosome
(c and f) that they
assort independently.
d
E
cb
a
Genes on the same
chromosome whose
alleles are so close together that they do not
assort independently
(such as a, b, and c) are
said to be genetically
linked.
Figure 12.UN05
© 2014 Pearson Education, Inc.