GENETICS

1. Prepared by :Mrs Bemina JA
Assistant Professor
ESIC College of Nursing
Kalaburagi
Review of genetics

2. GENETICS
 The study of heredity.
 Heredity – the passing of physical characteristics from
parents to offspring.
 Each characteristics is called a trait.

3. What determines our traits?
 Genes – the factors that control traits.
 The different forms of genes are called alleles
 An organism’s traits are controlled by the alleles in
inherits from its parents.
 Some alleles are dominate, while others are
recessive.

4. Types of Traits:
 Dominate vs. Recessive
 Dominate traits – a trait that always shows up when
the dominate allele is present.
 Recessive traits – a trait that is present only when no
dominate allele are present. Sometimes it is present but
hidden.

5. How to represent dominate or recessive alleles
 How to represent dominate or recessive alleles.
Dominate traits are capitalized.
 Ex. (Right handed = RH)
 Recessive traits are not capitalized.
 Ex. (Not right handed = rh)

6. Mendel
 Mendel – The Father of Genetics.
 Studied genetics by crossing pea plants.
 Found out traits are not a blend of their parents’
characteristics.

7. Different –otypes
 Phenotypes – organisms physical/visible traits.
 Genotypes – organisms genetic make up.
 Ex: Phenotypes could be – Brown eyes
 Genotype for that could be - BB

8. Types of Genotypes
 Homozygous – two identical alleles for a trait (Brown
eyes – BB)
 Heterozygous – two different alleles for a trait (Brown
eyes – Bb) Mendel called these hybrids
 Codominance
 The alleles are neither recessive nor dominate, they
both show up in an organisms offspring.

9. PUNNETT SQUARES
 Punnett square is a method for predicting the possible
genotypes of offspring.