Mendel conducted experiments with pea plants, observing seven characteristics with distinct variations. He cross-pollinated purebred plants with different characteristics, such as green and yellow pod plants. The resulting F1 generation always expressed one characteristic, such as green pods. When self-pollinating the F1 plants, the F2 generation expressed characteristics in predictable ratios, such as 3 green pods to 1 yellow pod. This supported Mendel's theory that inherited characteristics are determined by discrete units (genes and alleles) that segregate and are transmitted from parents to offspring.

3. LAW OF
SEGREGATION

4. MENDEL’S INITIAL
OBSERVATIONS
Mendel noticed that certain characteristics appeared to be
passed on from parents to offspring, in many species, and
wondered why this was so. He also wanted to establish what
characteristics were taken from each parent.
For the Mendel Pea Experiment he chose pea plants, because
they had some measurable characteristics as well as being easy
to breed and with a relatively short breeding period allowing a
quick experimental turn-around.
He measured seven of these characteristics, including seed-
shape, seed color, pod-color and pod-shape, each occurring in
two distinctive forms.

5. METHOD
To conduct the experiment, he cross pollinated the selected
pea plants by removing the anthers from one flower, to prevent
self-fertilization, and dusting pollen from another plant onto
the flower.
Initially, he cross-fertilized plants with the same characteristics
to ensure that the plants were true-breeding, giving a good
baseline for the research.
The next stage was to cross-pollinate plants with different
characteristics, such as one with green seed pods to one with
yellow seed pods.
These initial plants are called the P (Parental) generation. The
resulting offspring, the F1 (Filial generation) were then self
pollinated to produce the F2 generation. This self-fertilization
continued until the traits were established for many
generations.

6. MENDEL’S LAW OF
SEGREGATION

7. EXPERIMENTS WITH
PEA PLANTES
- Seed coat colour (gray or white)
- Seed shape (round or wrinkled)
- Seed colour (yellow or green)
- Pod colour (green or yellow)
- Flower position (axial or terminal)
- Pod shape (inflated or constricted)
- Stem length (tall or dwarf)

8. CROSS-POLLINATION OF
PUREBRED PLANTS
•cross-pollination between true breeding green and yellow pods
•all F1 green
F1 Generation
Gg = heterozygous

9. F2 GENERATION
• self-pollination of green F1 plants
• ¾ in F2 green, ¼ yellow
• 3 : 1 ratio in pod colour in F2
G = dominant = green
g = recessive = yellow
GG,gg=homozygous

10. SEED COLOUR
• C = dominant = yellow
•c = recessive = green

11. INHERITANCE PEA
COLOUR
Phenotype
genotype

12. RESULT FROM MENDEL’S
EXPERIMENT
Parental Cross F1 F2 Phenotypic Ratio F2
Phenotype Ratio
Round x Round 5474 Round : 2.96:1
Wrinkled Seed 1850 Wrinkled
Yellow x Green Yellow 6022 Yellow : 3.01:1
Seeds 2001 Green
Axial x Terminal Axial 705 Axial : 3.15:1
Flower Position 224 Terminal
Tall x Dwarf Tall l787 Tall : 2.84:1
Plants 227 Dwarf

13. MENDEL’S
GENERALIZATION
1. Alternative versions of genes account for variations in inherited
characters
- concept of alleles (G=green, g=yellow)
2. For each character, an organism inherits two genes, one from
each parent
- two gametes form somatic cells
- one allele comes from the mother, one from the father

14. MENDEL’S
GENERALIZATION
3. If the two alleles differ, then:
• dominant allele is fully expressed in the organism's
appearance (phenotype)
• recessive allele has no noticeable effect on the organism's
appearance (genotype)
4. The two genes for each character segregate during gamete
production
- ensures variation

15. LAW OF SEGREGATION
1. The pair of alleles of each parent separate and only one
allele passes from each parent on to an offspring
2. Which allele in a parent's pair of alleles is inherited is a
matter of chance
3. Segregation of alleles occurs during the process of gamete
formation (meiosis)
4. Randomly unite at fertilization

16. CROSS-POLLINATION OF
PUREBRED PLANTS
•cross-pollination between true breeding green and yellow pods
•all F1 green