GENETICS

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.

FATHER OF GENETICS

Gregory Mendel

Composed of 2

polymers of nucleotides.

Polymers are oriented

in antiparallel.

Molecule resembles a

spiral staircase of

complementary base

pairs.

DNA MOLECULE

“Double helix”

proposed by Watson

and Crick (1953).

Antiparallel

backbones.

Complementary

base pairing:

Adenine to Thymine

Cytosine to Guanine

STRUCTURE OF DNA

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

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

CLASSIFICATION OF

GENETIC DISEASES

Single gene defects/ Mendelian disorders

Disorders with multifactorial or polygenic

inheritance

Cytogenetic disorders

Disorders showing a typical patterns of

inheritance

VARIOUS DISEASES

ASSOCIATEDDiabetes mellitus

Hypertension

Gout

Congenital heart disease

Neural tube defects

Skeletal abnormalities

Coronary artery disease

Bipolar disorder

DIAGNOSIS OF GENETIC

DISEASE

FISH(Fluorescence in situ

hybridisation)

Conventional cytogenetic

analysis

Molecular analysis

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