Genetics PowerPoint

Important Vocabulary
Important Vocabulary

Genotype  Phenotype
There are exceptions
to these rules that will
be discussed
Two alleles make up one genotype
 Alleles are either dominant or recessive

Important Vocabulary

Genotypes are heterozygous or
homozygous
HH – homozygous dominant
Hh – heterozygous
hh – homozygous recessive

Gregor Mendel developed
many of the principles of
genetics during his research
on pea plants
Monohybrid Cross
A cross between parents that are homozygous
for different alleles of one trait
Complete Dominance – the dominant allele
is completely dominant over the recessive
allele
#1 - Complete Dominance
P:
F1:
RR  rr
Genotype
Phenotype
Rr
red
F1 Cross:
Rr  Rr
Punnett Square: R
r
F2:
R
RR
Rr
r
Rr
rr
Genotype
RR
Rr
Rr
rr
Type of Genotype
heterozygous
F2 Genotypic Ratio:
1 RR : 2 Rr : 1 rr
F2 Phenotypic Ratio:
3 red: 1 white
Phenotype
red
red
red
white
Type of Genotype
homozygous
heterozygous
heterozygous
homozygous
Monohybrid Cross
A cross between parents that are homozygous
for different alleles of one trait
Incomplete Dominance – the dominant and
recessive allele blend together
#4 - Incomplete Dominance
P:
F1:
RR  rr
Genotype
Phenotype
Rr
pink
F1 Cross:
Rr  Rr
Punnett Square: R
r
F2:
R
RR
Rr
r
Rr
rr
Genotype
RR
Rr
Rr
rr
Type of Genotype
heterozygous
F2 Genotypic Ratio:
1 RR : 2 Rr : 1 rr
F2 Phenotypic Ratio:
1 red: 2 pink : 1
Phenotype
red
pink
pink
Type of Genotype
homozygous
heterozygous
heterozygous
homozygous
Monohybrid Cross
A cross between parents that are homozygous
for different alleles of one trait
Codominance – both alleles are equally
dominant
#7 - Codominance
P:
F1:
RR  WW
Genotype
Phenotype
RW
red &
F1 Cross:
RW  RW
Punnett Square: R
W
R
W
F2:
RR
Type of Genotype
heterozygous
RW F2 Genotypic Ratio:
RW WW
Genotype
RR
RW
RW
WW
1 RR : 2 RW : 1 WW
F2 Phenotypic Ratio:
1 red : 2 red &
Phenotype
red
red &
red &
:1
Type of Genotype
homozygous
heterozygous
heterozygous
homozygous
Dihybrid Cross
A cross between parents that are homozygous
for different alleles of two traits
Complete Dominance
#8 - Complete Dominance
P:
F1:
yyrr  YYRR
Genotype
Phenotype Type of Genotype
YyRr
yellow/round heterozygous
YR
Yr
yR
yr
F1 Cross:
YyRr  YyRr
Punnett Square:
YR YYRR YYRr YyRR YyRr
YyRr
Yyrr
yR YyRR YyRr yyRR
yyRr
Yr
F2:
Genotype
9 Y_R_
3 Y_rr
3 yyR_
1 yyrr
YYRr
yr YyRr
Phenotype
yellow/round
yellow/wrinkled
green/round
green/wrinkled
YYrr
Yyrr
yyRr
yyrr
Additional Crosses
Sex Determination
Sex Linkage
ABO Blood Typing
#11 - Sex Determination
P:
XY  XX
X
X
X
XX
XX
Y
XY
XY
Ratio:
1 XX : 1 XY
Sex Linkage
Sex linked genes are located on either
the X or Y chromosome
 Most sex linked genetic disorders are
X-linked

X-Linked Genetic Disorders
Normal
XAXA
Carrier
XAXa
Affected
XaXa
XAY
XaY
#12 - Sex Linkage
P:
XHY  XHXh
Punnett Square:
XH
Xh
XH XHXH XHXh
Y
F1:
Genotype
XHXH
XHXh
XHY
XhY
XHY
XhY
Phenotype
normal
carrier
normal
hemophilia
Sex
F
F
M
M
Type of Genotype
homozygous
heterozygous
hemizygous
hemizygous
ABO Blood Typing
ABO Blood Typing
% of Blood Types in U.S. Caucasions
B+
9%
B2%
A6%
O+
38%
A+
34%
AB- AB+
1% 3%
O7%
ABO Blood Typing
RECIPIENT
A
D
O
N
O
R
A
B
Y
B
O
Y
Y
AB
O
AB
Y
Y
Y
Y
Y
Y
#15 - Blood Typing
P:
I Ai  I Bi
Punnett Square:
IB
F1:
i
IA
I AI B
I Ai
i
I Bi
ii
Genotype
IAIB
I Ai
I Bi
ii
Phenotype
AB
A
B
O
Polygenic
Inheritance
Examples:
Skin/Eye/Hair Color,
Height/Body Shape,
Rh (+/- Blood), etc.
Most human traits are
polygenically inherited
Pedigrees
Pedigrees
Normal
Affected
Carrier
Pedigrees
Example:
You are a normal female (homozygous). Both of your
parents are normal. Your younger brother is normal
and your older brother has hemophilia.
XHXh
XhY
XHY
XHY XHXH
You!
#18 - Pedigrees
XCXC
XcY
XCY
XCXc
XCY
XCXC
XCXc
XcY
You!
XCY
Chromosome Mapping
Chromosome
Map
8
%
9%
8
%
9%
#19 - Chromosome Mapping
Gene
Gene
A
B
C
D
E
A
-
8
12
4
1
B
8
-
4
12
9
C
12
4
-
16
13
D
4
12
16
-
3
E
1
9
13
3
-
3 1
D
8
EA
4
B
16
C
Recombinations
per 100
fertilized eggs
Download
Related flashcards

Population genetics

22 cards

Population genetics

25 cards

Mitochondrial diseases

16 cards

RNA

23 cards

Nucleobases

21 cards

Create Flashcards