Gregor Mendel conducted experiments with pea plants to study heredity and inheritance of traits. He found that traits are passed from parents to offspring through discrete units called genes. Mendel discovered that genes exist in pairs and can be dominant or recessive, and that they assort independently during reproduction. His work established the foundations of classical genetics and heredity.

1. MENDEL
and
HEREDITY

2. Gregor Mendel
 He is the Father of
GENETIC.
 He used Pea Plants (Pisum
sativum) for experiment.
He crossed Pea Plants
with different Traits.
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 Gregor Mendel (an Austrian
monk) made the first studies in
predicting how traits would transfer
from one generation to another.

3. What is GENETIC ?
Genetics is the study of HEREDITY.
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What is HEREDITY ?
The passing on of characteristics
(traits) from parents to offspring.

4. WHY MENDEL USED PEA PLANT FOR
HER EXPERIMENT ?
o They have two distinct, male and female, sex cells
called gametes.
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o Pea plants are also inexpensive, easy to
maintain, and grow quickly.
o Mendel used pea plants because they easily
known each of its traits.

5. 5
Mendel controlled the
fertilization of his pea plants
by removing the male parts,
or stamens.
He then fertilized the female
part, or pistil, with pollen from
a different pea plant.

6. 6
Pea Plant can harvest for only 12 to 15 Weeks.

7. Characteristic of Pea Plant
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8. He crossed Pea Plants with
different Traits
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• Fertilization - the
uniting of male and
female gametes
(sex cell).
• Cross - combining
gametes from
parents with
different traits.

9. P1 = parent in the 1st generation
 The offspring of P1 were called the F1
generation
“F” stands for filial
Filial stands for son or daughter
 The offspring of the cross between 2
F1 plants were called the F2 generation
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10. 10
What Did Mendel Find?
He discovered different laws and rules
that explain factors affecting heredity
Each organism has two alleles for each trait
Alleles - different forms of the same gene.
Genes - Units responsible for passing on traits from
one generation to the next.
Rule of Unit Factors

11. 11
Rule of Dominance
Dominant Alleles
In heterozygote, the allele that is fully
expressed in the phenotype.
The letter should be (uppercase)
Recessive Alleles
In the homozygous, its expression
masked in the presence of a dominant
gene.
The Letter should be (lowercase)

12. 12
LAW OF SEGREGATION
The offspring then receives its own pair of
alleles for that trait. Whichever of the two
alleles in the offspring is dominant determines
how the offspring expresses that trait (e.g.
the color and height, etch.).

13. 13

14. 14
State that allele pairs separate
independently during the formation of
gametes. this means that traits are
transmitted to offspring independently of
one other.
Law of Independent
Assortment

15. 15

16. 16
oGenotype:the gene combination of an organism.
o-AA or Aa or aa
oPhenotype: the way an organism looks.
o-red hair or brown hair
Genotype and Phenotype

17. 17
Homozygous and Heterozygous
oHomozygous: if the two alleles for a trait are
the same (TT or tt)
oHeterozygous: if the two alleles for a trait are
different (Tt)

18. 18
Homozygous
Heterozygous

19. Dihybrid vs Monohybrid
• Dihybrid Cross -
crossing parents who
differ in two traits
(AAEE with aaee)
• Monohybrid Cross -
crossing parents who
differ in only one trait
(AA with aa)

20. 20

21. 21
In some species of plants, tall plants
are dominant to short plants. Predict
the outcomes between a homozygous
dominant plant and a short plant.
TT x tt
T = tall dominant plant
t = short plant
Genotype- 100 % Tall
Phenotype- Tall