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11/7/2011
BIOLOGY 3 CH-9 REVIEW
WORKSHOP
Contents
Genetic Concepts
Single Gene Inheritance
Multiple Gene Inheritance
Sex-linked Inheritance
Figure B: Anatomy of pea plant
Character
Figure A: Gregor Mendal; “the
father of modern genetics”
Trait
Color
Purple
# of stamen
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Table 1: Examples of characters and
traits of Figure B
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Character
Trait
Table 2: The seven pea
characters studied by Mendal
Figure C: Crosses taking one character (flower color)
Alleles
P
p
Table 3: Possible alleles
Genotype
PP
Phenotype
Purple
Pp
Purple
pp
White
Table 4: Possible genotypes
and phenotypes
Figure D: Explains Figure C in terms of allele
distribution; discussing genotypes and
phenotypes
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Homologous Chromosomes – Alleles
Table 5: Explanation of Figure E
Figure E: Homologous Chromosomes with
labeled components
Homologous Pairs
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Chromosomes
2
Gene Loci
3
Alleles
P, a, B, b
Genotypes
PP, aa, Bb
The Punnet Square___
Gg x Gg
G
Alleles
g
Genotypes
G (Dom)
GG
g (Rec)
Gg
gg
Phenotypes
G
GG
Gg
GG
Green Eyes
Gg
Green Eyes
gg
Blue Eyes
Genotypes
g
Gg
gg
Phenotypes
Prob.
GG
Green Eyes
25%
Gg
Green Eyes
50%
gg
Blue eyes
25%
Independent Assortment
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Inherited Disorders
Figure F: Child with Cystic
Fibrosis (Recessive Disorder)
Figure G: Dr. Michael C. Ain
Achondroplasia (Dominant Disorder)
Incomplete Dominance
Genotypes
Phenotypes
RR
Rr
rr
Pleiotropy
Text H: Sickle-Cell disease; example of a pleiotropy (single gene
influencing multiple characters)
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Polygenic Inheritance
Linked Genes
Crossing Over
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Crossing Over (cont.)
Sex Chromosomes
Sex-linked Genes
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