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 Genom Quantitative Genetics Meiosis + mitosis DNA structure Population Genetics Sex determination Chemistry of DNA Evolution Sex linkage Transcription Speciation Chromosomal mapping Translation Cytogenetics Control of gene expression DNA cloning

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 ? Molecular Biology? 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 Classical: Reverse: biological process identify mutants Classical: find the gene biochemical function gene in hand Reverse: create mutants biological process phenotype?

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 whether it really does it in vivo It doesn’t tell you how direct the role is

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

B – D → 45 – 80 (Normal distribution) Grading system Grade : 0 – 100 A > 80 B – D → 45 – 80 (Normal distribution) E < 45 Grade composition Home work : 30 Mid-term Final Exam 40