INTRODUCTION TO PLANT MOLECULAR GENETICS

Why young breeders must study genetics?

Genetics Branch of biology dealing with heredity and variation Branch of biology dealing with heredity and variation Branch of biology dealing with the study of the gene Branch of biology dealing with the study of the gene Center of Genetics: Unit of heredity Nucleic acid Protein synthesis Characteristics of organisms Relationship between genes and traits Genetics is a broad discipline It encompasses molecular, cellular, organism, and population

Three Major Areas of Genetics Classical Genetics (Transmission) Molecular GeneticsEvolutionary Genetics Mendel’s PrinciplesGenomQuantitative Genetics Meiosis + mitosisDNA structurePopulation Genetics Sex determinationChemistry of DNAEvolution Sex linkageGene expressionSpeciation Chromosomal mapping Control of gene expression CytogeneticsDNA cloning & Marker

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. Evolutionary genetics: focus on the study of genetic basis of changes in organism over time   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 ? The field of biology that studies the structure and function of genes at a molecular level. Study of the expression, regulation and inheritance of genes at the level of DNA and its transcription products Study of gene structure, function and regulation – below the organism level Study of genes and how they are expressed Study of molecular basis of inheritance Molecular genetics Basis of Modern Breeding

Modern Breeding Systematic procedures used to improve trait phenotypes by crossing and selection, directed manipulation of the genotype at the DNA sequence level, and introduction of new genes. Systematic procedures used to improve trait phenotypes by crossing and selection, directed manipulation of the genotype at the DNA sequence level, and introduction of new genes.

Developing suitable cultivars Each cultivar is developed with special purpose Each cultivar is developed with special purpose Each cultivar responses differently to environmental change Each cultivar responses differently to environmental change Climate Change needs special cultivars Climate Change needs special cultivars If breeding work fails to help improving resource utilization efficiency and tackling the effect of global warming, then agriculture will probably not be sustainable and as a result the size of global community will decline as resources are exhausted and environment is not friendly anymore to human being (Beversdorf, 1994). Breeding needs advance technology

Molecular Genetics: A Short History 1869 Miescher isolated DNA for the first time 1944 Avery provided evidence that DNA is the genetic material 1953 Watson and Crick proposed the double helix as the structure of DNA 1957 Kornberg discovered DNA polymerase 1961 Marmer and Doty discovered DNA renaturation 1962 Arber, Nathans and Smith discovered restriction endonucleases 1966 Nirenberg, Ochoa, and Khorana figured out the genetic code.

Molecular Genetics: A Short History 1967 Geller discovered DNA ligase Boyer, Cohen and Berg develop DNA cloning techniques 1975 Southern developed gel-transfer hybridization Sanger and Barrel and Maxam and Gilbert developed rapid DNA sequencing methods Palmiter and Brinster produced transgenic mice Spradling and Rubin produced transgenic fruit flies 1985 Mullis and colleagues invented the Polymerase Chain Reaction (PCR)

Molecular Genetics: A Short History 1990 Human Genome Project 1995 Microarray technique by Brown and Davis 2000 Arabidopsis and Drosophila genome project 2000 The first gene controlling a quantitative trait is cloned by Tanksley 2002 The draft of rice genome sequence is published The development of sequencing by synthesis technology

The Molecular Basis of Inheritance?

GenomeGenes, regulatory sequencesOthers? The Molecular Basis of Inheritance ? RNA Polypeptides

1.Genome 2.Chromosome 3.Gene 4.DNA/RNA 5.Nucleic Acid 6.Protein 7.Amino Acid The Molecular Basis of Inheritance?

Genome Total genetic information carried by a single set of chromosome in a haploid nucleus Chromosome A DNA – histone protein thread, usually associated with RNA, occurring in the nucleus of a cell Chromosomes contain hundreds of genes encoded within their DNA. Gene segment of a chromosome that contains the heredity traits of an organism DNA Double stranded form of genetic material of organisms The Molecular Basis of Inheritance ?

RNA Single stranded form of genetic material of organisms result of the DNA transcription Nucleotide Unit structure of nucleic acid Protein a polymer that has a high relative molecular mass of amino acids Polypeptide a linear polymer that consists of ten or more amino acids linked by peptide bonds Amino Acid An organic compound containing an acidic carboxyl group and a basic amino group The Molecular Basis of Inheritance ?

INTRODUCTION TO MOLECULAR GENETICS Genome Genome Genetic Material (DNA & RNA) Genetic Material (DNA & RNA) DNA structure DNA structure Chemistry of DNA Chemistry of DNA Gene expression (transcription and translation) Gene expression (transcription and translation) Control of gene expression Control of gene expression Molecular tool Molecular tool DNA cloning DNA cloning DNA marker DNA marker

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