1. Genetics and Heredity

2. Are these inherited traits?
Eye Color
Hair Texture & Color
Height
Musical, athletic,
And artistic ability
Personality

3. These are questions that Gregor Mendel
*Think About This*…
“My parents have brown eyes, why do I have blue?”
“My brother is tall, why am I short?”
“Why does my sister have blonde hair while mine is brown?”
These are questions that Gregor Mendel
tried to answer…

4. Mendel’s Studies Studied Garden Pea plant in three generations:
P Generation- The parental generation
F1 Generation- The offspring of the parental generation
Mendel studied the garden pea plant in three generations:
P generation: parental generation
F1 generation- the offspring of the parental generation
F2 generation- the offspring of the F1 generation from self-pollination
F2 Generation- The offspring of the F1 generation
from self-pollination

5. Phenotype: Physical Appearance
An individual is determined by
the alleles that code for a specific
trait:
Eyes
Phenotype is the physical appearance of an organism.
Hair
Skin Color

6. Genotype: the set of alleles you contain (genes or genetic makeup)
Mendel concluded that
an individual contains
2 genes (1 from each
parent) for each trait.
Letters of the alphabet
are used to represent
alleles of a genotype
Capital letters are for
dominant alleles
Lowercase letters are
for recessive alleles
For example, the gene
for brown eyes is dominant
over the gene for blue eyes.
If you have blue eyes,
your genotype is bb.
Genotype: the set of alleles you have and they determine your genetic makeup.
Mendel concluded that an individual contains 2 genes (1 from each parent) for each trait.
Letters of the alphabet are used to represent alleles of a genotype.
Capital letters are for dominant alleles
Lowercase letters are for recessive alleles
For example, the gene for brown eyes is dominant over the gene for blue eyes. If you have blue eyes, your genotype is bb.
Brown eyes can be BB or Bb.
BB= brown eyes
Bb= brown eyes
bb= blue eyes

7. Mendel’s studies led to:
Recessive (h)
Dominant (H) -
Homozygous- same (HH or hh) -
Heterozygous- different (Hh)
Phenotype (blonde, red, brown)
Genotype (HH, Hh or hh) -
Purebred (HH or hh)
Hybrid (Hh) -

8. Theory of Heredity Inherited allele for purple P
HOMOZYGOUS purple flower PP

9. Theory of Heredity Inherited allele for pink flower p
HOMOZYGOUS pink flower pp

10. Theory of Heredity Inherited allele for purple P
Inherited allele for pink flower p
HETEROZYGOUS purple flower Pp

11. Predicting Heredity
Probability

12. Probability
The likelihood that a specific event will occur.
Probability = # of times event occurs
# of possible outcomes
Ex: What is the probability that a coin will
be heads? ? OR ?
50%
1/2

13. Genotypic Ratio: compares all possible allele combinations
Homozygous dominant : Heterozygous
Phenotypic Ratio: compares all possible physical characteristics
# showing dominant trait : # showing recessive trait

14. Monohybrid Cross
a cross that shows the possible offspring for ONE trait A a
Aa X Aa
Mom Dad Aa A AA
A: White Fur
a: Brown Fur Aa aa a
Genotypic Ratio:
1:2:1
Phenotypic Ratio:
3 white : 1 brown

15. Practice!! Cross a HOMOZYGOUS dominant female with a
HETEROZYGOUS male using the same trait. A A
What is the genotypic ratio? AA A AA
2:2 or 1:1
AA:Aa
What is the phenotypic ratio Aa Aa a
4:0
white fur: brown