THE MONOHYBRID CROSS

1
THE MONOHYBRID CROSS

• FOLLOWING THE INHERITANCE OF ONE TRAIT

2
TODAYS BIG WORDS

• MONOHYBRID
• ALLELE
• DOMINANT
• RECESSIVE
• HOMOZYGOUS
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

3
CROSSING TWO PLANTS
SHORT
TALL
X
PARENTS
ALL TALL
OFFSPRING
4
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE
• DOMINANT
• RECESSIVE
• HOMOZYGOUS
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

5
ADD THE SYMBOLISM
SHORT
TALL
X
PARENTS
TT
tt
ALL TALL
OFFSPRING
Tt
6
EGGS AND POLLEN???
SHORT
TALL
X
PARENTS
TT
tt
T
t
GAMETES
ALL TALL
OFFSPRING
Tt
7
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT
• RECESSIVE
• HOMOZYGOUS
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

8
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE
• HOMOZYGOUS
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

9
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE Trait that can hide
• HOMOZYGOUS
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

10
THE PUNNETT SQUARE
GAMETES GO HERE


11
THE PUNNETT SQUARE
OFFSPRING GO HERE


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THE PUNNETT SQUARE
T T
t Tt Tt
t Tt Tt
13
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE Trait that can hide
• HOMOZYGOUS Has the same alleles
• HETEROZYGOUS
• GENOTYPE
• PHENOTYPE

14
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE Trait that can hide
• HOMOZYGOUS Has the same alleles
• HETEROZYGOUS Has different alleles
• GENOTYPE
• PHENOTYPE

15
CROSSING TWO OFFSPRING
TALL
TALL
X
PARENTS
???????
OFFSPRING
16
EGGS AND POLLEN???
TALL
TALL
X
PARENTS
Tt
Tt
T
t
GAMETES
t
T
17
POTENTIAL FOR DIFFERENT OFFSPRING
TALL
TALL
X
PARENTS
Tt
Tt
T
t
GAMETES
t
T
OFFSPRING
TT
TALL
18
POTENTIAL FOR DIFFERENT OFFSPRING
TALL
TALL
X
PARENTS
Tt
Tt
T
t
GAMETES
t
T
OFFSPRING
Tt
TALL
19
POTENTIAL FOR DIFFERENT OFFSPRING
TALL
TALL
X
PARENTS
Tt
Tt
T
t
GAMETES
t
T
OFFSPRING
tt
SHORT
20
THE PUNNETT SQUARE
T t
T
t
21
THE PUNNETT SQUARE
T t
T TT Tt
t Tt tt
22
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE Trait that can hide
• HOMOZYGOUS Has the same alleles
• HETEROZYGOUS Has different alleles
• GENOTYPE GENE TYPE (the letters)
• PHENOTYPE

23
TODAYS BIG WORDS

• MONOHYBRID Following one trait
• ALLELE One form of a gene
• DOMINANT Trait that always shows up
• RECESSIVE Trait that can hide
• HOMOZYGOUS Has the same alleles
• HETEROZYGOUS Has different alleles
• GENOTYPE GENE TYPE (the letters)
• PHENOTYPE WHAT IT LOOKS LIKE

24
PHENOTYPES
T t
T TT tall Tt tall
t Tt tall tt short
25
GENOTYPES
T t
T TT Homozygous dominant Tt Heterozygous
t Tt Heterozygous Tt Homozygous recessive