Transcript introduction to molecular genetics

INTRODUCTION TO
MOLECULAR GENETICS
Gene
 The hereditary determinant of a specified difference between
individual
 The basic unit of heredity
 The unit which passed from generation to generation following
simple Mendelian inheritance
 A segment of DNA which encodes protein synthesis
 Any of the units occurring at specific points on the
chromosomes, by which hereditary characters are transmitted
and determined, and each is regarded as a particular state of
organization of the chromatin in the chromosome, consisting
primarily DNA and protein
Genetics
The study of heredity
The study of how differences between
individuals are transmitted from one
generation to the next
The study of how information in the genes is
used in the development and functioning of
the adult organism
Three Major Areas of
Genetics
Classical Genetics
(Transmission)
Molecular Genetics Evolutionary
Genetics
Mendel’s Principles
Meiosis + mitosis
Genom
DNA structure
Quantitative Genetics
Population Genetics
Sex determination
Chemistry of DNA
Evolution
Sex linkage
Transcription
Chromosomal mapping Translation
Cytogenetics
Control of gene
expression
DNA cloning
Speciation
Major Subdisciplines of Genetics
 Transmission Genetics: focuses on the
transmission of genes and chromosomes in
individuals from generation to generation.
 Molecular Genetics: focuses on the structure and
function of genes at the molecular level.
 Population Genetics: focuses on heredity in
groups of individuals for traits determined by one
or only a few genes.
 Quantitative Genetics: focuses on heredity in
groups of individuals for traits determined by many
genes simultaneously.
Molecular Genetics ?
Understanding the molecular basis of biological processes
through studies on the gene
Study of gene structure, function and regulation – below the
organism level
Study of genes and how they are expressed
The Molecular Basis of Genetics
Molecular Biology?
Study of molecules in cells
Two broad approaches
biological
Classical: process
Reverse: gene
in hand
identify
mutants
create
mutants
find
the gene
phenotype?
biochemical
function
biological
process
Classical Method

Genotype
Phenotype
• Discover new phenotype
• Prove that it has genetic basis (i.e. that you discovered a
new mutation)
• Find the gene that has mutated
• Understand what and how the wild type gene does
Classical Method

Genotype
Phenotype
• Discover new phenotype
• Prove that it has genetic basis (i.e. that you
discovered a new mutation)
• Find the gene that has mutated
• Understand what and how the wild type gene does
Reverse genetics

Genotype
•
•
•
•
Phenotype
Change something in a known gene
Observe phenotypic effect
Find out why you see what you see
Understand what and how the wild type gene does
Reverse genetics

Genotype
•
•
•
•
Phenotype
Change something in a known gene
Observe phenotypic effect
Find out why you see what you see
Understand what and how the wild type gene does
Genetics
Biochemistry
Gene products are studied in vivo
through the genes that encode
them
Gene products are purified and
studied in vitro
Genetic analysis tells you that
the product has a role in the
process
Biochemistry tells you what a
protein can do in vitro
It doesn’t tell you how direct the
role is
It doesn’t tell you whether it
really does it in vivo
INTRODUCTION TO MOLECULAR
GENETICS
 Genome
Genetic Material (DNA & RNA)
 DNA structure
Chemistry of DNA
 Transcription and translation
 Control of gene expression
 Molecular tool
 DNA cloning
Grading system
Grade : 0 – 100
 B–D
 A > 80
→ 45 – 80 (Normal distribution)
 E < 45
Grade composition
Home work
Mid-term
Final Exam
:
:
:
30
30
40