1042_SCG_2024%3B+Module+2+Lecture+1_JMA.pdf

1042SCG Genetics and Evolutionary Biology Module 2 Lecture 1: central dogma Dr. John Atack Institute for Glycomics & School of Environment and Science central dogma Central Dogma Chromosomes ► DNA, protein and sometimes RNA ► A unit of inheritance ► Where genes are usually located Review:...

1042SCG Genetics and Evolutionary Biology Module 2 Lecture 1: central dogma Dr. John Atack Institute for Glycomics & School of Environment and Science central dogma Central Dogma Chromosomes ► DNA, protein and sometimes RNA ► A unit of inheritance ► Where genes are usually located Review: Nucleic Acids and Amino Acids 1 2 3 4 Review: Central Dogma 1 2 3 4 Review: Central Dogma 1 2 DNA RNA Protein 3 4 Central Dogma DNA RNA Protein Central Dogma DNA Transcription DNA to RNA RNA Protein Central Dogma DNA Transcription DNA to RNA RNA Translation RNA to protein Protein Central Dogma DNA Transcription DNA to RNA Gene RNA expression Translation RNA to protein Protein Central Dogma DNA replication DNA to DNA DNA Transcription DNA to RNA Gene RNA expression Translation RNA to protein Protein Central Dogma DNA replication DNA to DNA Perpetuation to next generation DNA Transcription DNA to RNA Gene RNA expression Translation RNA to protein Protein Central Dogma DNA replication DNA to DNA Perpetuation to next generation DNA Reverse Transcription Transcription RNA to DNA DNA to RNA Gene RNA expression Translation RNA to protein Protein Replication, expression, mutation The genetic material must perform three essential functions: Replication, expression, mutation The genetic material must perform three essential functions: ► thegenotypic function — replication (each cell or even kernel must be replicated from a single cell into daughter cells) Replication, expression, mutation The genetic material must perform three essential functions: ► thegenotypic function — replication (each cell or even kernel must be replicated from a single cell into daughter cells) ► the phenotypic function — gene expression (genes control shape and colour of kernel) Replication, expression, mutation The genetic material must perform three essential functions: ► thegenotypic function — replication (each cell or even kernel must be replicated from a single cell into daughter cells) ► the phenotypic function — gene expression (genes control shape and colour of kernel) ► theevolutionary function — mutation (through mutations different kernel colours are achieved) What is a gene? W h a ► Gregor Mendel: the rules of inheritance. A gene is t the “unit factor” that controls ai specific phenotypic trait s a ► James Watson and Francis Crick: G the structure of DNA e n ► The Human Genome Project:e the detailed analysis of human DNA ? ► Genome Editing (CRISPR/Cas9) What is a gene? What is a gene? What is a gene? What is a gene? What is a gene? What is a gene?  What is a gene? § The concept of the gene has undergone many refinements since Mendel ’ s discovery of “unit factors” § One Gene-One Enzyme – Archibald Garrod (inherited disease of metabolism) - mutations in genes encoding enzymes produce metabolic block § Phenylketonuria is caused by the absence of phenylalanine hydroxylase)  What is a gene? § The concept of the gene has undergone many refinements since Mendel ’ s discovery of “unit factors” § One Gene-One Enzyme – Arichbald Garrod (inherited disease of metabolism) - mutations in genes encoding enzymes produce metabolic block § Phenylketonuria is caused by the absence of phenylalanine hydroxylase)  What is a gene? § The concept of the gene has undergone many refinements since Mendel ’ s discovery of “unit factors” § Refined to One Gene-One Polypeptide or One Gene-One Transcript through experiments by Beadle & Tatum  What is a gene? § The concept of the gene has undergone many refinements since Mendel ’ s discovery of “unit factors” § Refined to One Gene-One Polypeptide or One Gene-One Transcript through experiments by Beadle & Tatum § Experiments in bread mould Neurospora crassa § Mutations lead to distinct phenotypes  What is a gene? § The concept of the gene has undergone many refinements since Mendel ’ s discovery of “unit factors” § Further refinement by Vernon Ingram in 1950’s – work on sickle cell anaemia § Overlapping and genes-within-genes (1960’s) § Sequencing of eukaryotic genes led to discovery of introns (1970’s) by Richard Roberts  What is a gene? § Modern definition – ‘a region of DNA that encodes for at least one transcript and/or at least one polypeptide’  Concept of a gene - refinements § Thomas Hunt Morgan - genes exist on chromosomes Chromosome composition § Chromosomes contain proteins and nucleic acids. § The nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Which component is the genetic material?  Concept of a gene - refinements Which component is the genetic material? Four major experiments – 1. Griffith, Sia, Dawson – transformation principal  Concept of a gene - refinements Which component is the genetic material? Four major experiments – 1. Griffith, Sia, Dawson – transformation principal 2. Avery, MacLeod, McCarty – DNA is the transforming agent  Concept of a gene - refinements Which component is the genetic material? Four major experiments – 1. Griffith, Sia, Dawson – transformation principal 2. Avery, MacLeod, McCarty – DNA is the transforming agent 3. Hershey and Chase – DNA is the genetic material  Concept of a gene - refinements Which component is the genetic material? Four major experiments – 1. Griffith, Sia, Dawson – transformation principal 2. Avery, MacLeod, McCarty – DNA is the transforming agent 3. Hershey and Chase – DNA is the genetic material 4. Fraenkel-Conrat – RNA can also act as genetic material  Concept of a gene - refinements Which component is the genetic material? Four major experiments – 1. Griffith, Sia, Dawson – transformation principal 2. Avery, MacLeod, McCarty – DNA is the transforming agent 3. Hershey and Chase – DNA is the genetic material 4. Fraenkel-Conrat – RNA can also act as genetic material See: Campbell 11th Ed pg 317-319; Snustad 6th Ed pg 173-174 & pg 193-197; Pierce 6th Ed pg 291-294. Also “Additional Resources” in “Module 2 folder” under Course Content  Summary § Gene – basic genetic unit ‘a region of DNA that encodes for at least one transcript and/or at least one polypeptide’  Next Lecture § Go over key experiments that demonstrated that - DNA encodes genes DNA is the genetic material