Genetics is the branch of biology that deals with heredity and the variation of inherited characteristics. Gregory Mendel is considered the father of genetics. The DNA molecule has a double helix structure proposed by Watson and Crick in 1953, with two antiparallel backbones connected by complementary base pairing between adenine and thymine and cytosine and guanine. Changes to DNA can cause genetic conditions like Down syndrome, cystic fibrosis, and sickle cell anemia. Genetic testing involves extracting DNA from cells, cutting it up, separating fragments, and analyzing them to diagnose genetic diseases.

1. GENETICS

2. WHAT IS GENETICS??
Thai branch of biology that
deals with heredity,
especially the mechanisms
of hereditary transmission
and the variation of
inherited characteristics
among similar or related
organisms.

3. FATHER OF GENETICS
Gregory Mendel

5. Composed of 2
polymers of nucleotides.
Polymers are oriented
in antiparallel.
Molecule resembles a
spiral staircase of
complementary base
pairs.
DNA MOLECULE

6. “Double helix”
proposed by Watson
and Crick (1953).
Antiparallel
backbones.
Complementary
base pairing:
Adenine to Thymine
Cytosine to Guanine
STRUCTURE OF DNA

7. Abnormal number of chromosomes
-Down’s syndrome, Edwards syndrome,
Deletion
-Cri Du chat, Williams syndrome
Sex Chromosome Abnormalities
-Turner syndrome, Klinferlter’s syndrome
Single Gene Mutations
-Cystic Fibrosis, Sickle Cell anaemia
EXAMPLES OF CONDITIONS
CAUSED BY DNA CHANGES

8. GENETIC TESTING AND
PROFILING
Take a sample of cells (blood,
hair root)
Extract the DNA from cells
Cut up the DNA
Separate the DNA fragments
Analyse the DNA fragments

9. CLASSIFICATION OF
GENETIC DISEASES
Single gene defects/ Mendelian disorders
Disorders with multifactorial or polygenic
inheritance
Cytogenetic disorders
Disorders showing a typical patterns of
inheritance

10. VARIOUS DISEASES
ASSOCIATED
Diabetes mellitus
Hypertension
Gout
Congenital heart disease
Neural tube defects
Skeletal abnormalities
Coronary artery disease
Bipolar disorder

11. DIAGNOSIS OF GENETIC
DISEASE
FISH(Fluorescence in situ
hybridisation)
Conventional cytogenetic
analysis
Molecular analysis

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