Law of Dominance - Recessive alleles will always be masked by dominant alleles . Law of Segregation - At the time of gametes formation the two copies of each hereditary factor segregates so that offspring get one factor from each parent . Law of Independent Assortment - Genes for one trait are not inherited together with another trait .

1. *Welcome to my channel
Biology Simplify

2. Law of Dominance
Law of Segregation
Monohybrid Cross
Law of Independent Assortment
Dihybrid Cross

3. Law of Dominance
Recessive alleles will always be masked by Dominant alleles
TT tt (pure parents P generation)
½ T ½ T ½ t ½ t (gametes)
cross
T
T
t t
Tt Tt
Tt Tt
F1 generation – Tt 100% Tall (hybrid)
Genotype – 4 : 0
Phenotype – 4 : 0
Tall Short

4. Mendel’s 1st Law
Law of Segregation
Key concepts: At the time of gametes formation the two copies of
each hereditary factor(Gene)Segregate so that offspring get one
factor from each parent.
Diploid organisms –
chromosomes occur in
Homologous pairs.
Meiosis –
homologous chromosomes separate ,
as a result pairs of alleles separate.

5. Monohybrid Cross (Single Trait)
Law of Segregation
TT Tt
Tt tt
T
t
T t TT tt
Tall Short
T (gametes) t t
Tt F1
Tt Tt
Self cross
F2 Phenotype : - 3 Tall : 1 Short F2 Genotype : - 1 Pure Tall : 2 Hybrid Tall : 1 Short
P
F2
T
100%
Tall
A cross b/w pure breed
pea plant, Homozygous
Tall( TT) & Homozygous
Short (tt)
P Gen- one type
gametes.
F1- all Hybrid Tall
offspring.
F1 - two type gametes.
F2- both Tall & Short
offspring .(after Self
cross of F1 offspring)

6. Mendel’s 2nd Law
Law of Independent Assortment
Independent Assortment : No mixing ,No association
Key concept : This law states that genes for one trait are not
inherited together with another trait.
Dihybrid Cross : Segregation of seed color is independent of the seed
shape, both parental and new combinations of characters appear in f2
offspring i.e. Assortment of gene of a pair is independent of the other pair.

7. Dihybrid Cross (Two Traits)
Law of Independent Assortment
P: YY RR yy rr
Yellow, green,
Round wrinkled
YR yr (gametes)
F1 YyRr self cross
yellow,
round
YYRR
YR Yr yR yr
YR
Yr
yR
yr
YYRr
YyRR YyRr
YYRr YYrr YyRr Yyrr
YyRR
YyRr
yyRR yyRr
YyRr Yyrr yyRr yyrr
F2 Phenotype – 9: 3: 3 : 1
F2 Genotype- 1: 2:1: 2: 4: 2: 1: 2: 1
F2

8. Incomplete Dominance & Co-dominance