1 A Molecular View of GeneticsShuchismita Dutta, Ph.D.

2 Learning Objectives DNA to Genome Gene to Protein Mutations and Variations Genetic Engineering

3 Learning Objectives DNA to Genome Gene to Protein Mutations and Variations Genetic Engineering

4 Genetic Timeline Learn more about the genetics timeline at https://www.genome.gov/pages/education/genetictimeline.pdf and

5 DNA: Deoxyribose Nucleic AcidMost commonly used genetic material Inherited from parents Stored inside cells (nucleus, mitochondria) Read-only memory Duplicated by DNA polymerase Deoxyribose in backbone DNA Learn more about DNA at

6 RNA: Ribonucleic Acid Ribose sugar in backboneProduced by transcription (RNA polymerase) Different types in cell mRNA tRNA rRNA snRNA May acts as enzymes May be carrier of genetic information too (some virus) tRNA Learn more about tRNA at

7 Components of Nucleic AcidBase Sugar Phosphate

8 Basis of Biology and InheritanceBase-pairing A-T G-C Replication Both strands make complementary DNA Transcription Coding strand makes mRNA Translation tRNA recognizes specific codon on mRNA Learn more about nucleic acid base pairing at A: denotes hydrogen bond acceptor D: denotes hydrogen bond donor

9 The Packing Problem Single human cell  pack 6ft of DNANucleosome Single human cell  pack 6ft of DNA DNA condensed by wrapping on special proteins (histones)  nucleosomes Nucleosomes pack further to make a chromosome Learn more about Nucleosomes at

10 Gene, Chromosome and GenomeUnit of DNA that carries the instructions for making a specific protein or set of proteins Chromosome Made of protein and a single molecule of DNA. Genome An organism's complete set of DNA Human genome has ~3 billion DNA base pairs Learn more about Chromosomes at https://www.genome.gov/ / Learn more about genomics at https://www.genome.gov/ /a-brief-guide-to-genomics/ https://www.genome.gov/images/content/chromosome_1_factsheet.jpg

11 Learning Objectives DNA to Genome Gene to Protein Mutations and Variations Genetic Engineering

12 Post translational processingFrom Gene to Protein 3. Peptide bond formation Transcription 2. Delivery of tRNA-aa 4. Push peptide bound tRNA Repeat 1. Initiate Translation Translation Protein Learn more about RNA Polymerase at Learn more about Ribosomes and Protein Synthesis at Post translational processing End. Terminate Protein Synthesis

13 Post-Transcriptional Processing – 1 7 methyl Guanosine -Cap To protect RNA from cleavage To recognize beginning of mRNA (5’) 3 steps and 3 enzymes involved Poly A Tail Binds polyA binding protein to protect from cleavage Long tail of adenine nucleotides at end of mRNA (3’) 1.Phosphatase 2. guanosyl transferase 3. (guanine-N7-)-methyltransferase Learn more about the mRNA Cap at Learn more about Poly A Polymerase at Poly(A) polymerase

14 Post-Transcriptional Processing - 2EM structure of yeast Spliceosome, Sept. 2016 Splicing Processing by spliceosome (snRNA + proteins) introns removed from pre-mRNA Example of insulin gene on human Chromosone 11 shown below. Chromosome 11 INS Gene

15 Learning Objectives DNA to Genome Gene to Protein Mutations and Variations Genetic Engineering

16 Mutations Normal DNA TGA … GGA … CTC … CTC … mRNA ACU … CCU … GAG … GAG … Prot Thr Pro Glu Glu Mutant DNA TGA … GGA … CAC … CTC … mRNA ACU … CCU … GUG … GAG … Prot Thr Pro Val Glu Permanent change in gene  altered protein structure and function Mutation in gene Transition (AG or CT) Transversion (A/G C/T) Deletion/Insertion Change in protein Synonymous - sequence same Missense – sequence altered Non-sense – insert stop codon Learn more about hemoglobin and sickle cell anemia at Hemoglobin Sickle Cell Hemoglobin

17 Human Genetic VariationsAll humans are genetically unique (except identical twins) Polymorphisms or genetic differences Single nucleotide polymorphisms (SNP) Indels ( insertions, deletions), duplications, and rearrangements occur less frequently Learn more about Human Genetic Variations at https://www.ncbi.nlm.nih.gov/books/NBK20363/ https://omim.org/allelicVariant/141900

18 Learning Objectives DNA to Genome Gene to Protein Mutations and Variations Genetic Engineering

19 Genetic Timeline Robert Swanson and Herbert BoyerLearn more about the genetic timeline at https://www.genome.gov/pages/education/genetictimeline.pdf Robert Swanson and Herbert Boyer

20 Making Recombinant Insulin

21 Genetic Engineering TodayGenetics Tools Applications For Cutting: Restriction endonucleases (RE) Zinc finger nucleases (ZFN) Transcription Activator Like Effector Nucleases (TALEN) Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) For amplification: Polymerase chain reactions For exploring and archiving: cDNA libraries Research: Protein production; Tracking function Agriculture: Disease resistance; increased production Industry: Production of large quantities of various proteins Medicine: Diagnose details of diseased states; change genomic DNA to treat diseases (Trials ongoing) Environment: Engineer special enzymes that can process environmental pollutants/contaminants

22 Mutations and Variations Genetic EngineeringSummary DNA to Genome DNA Structure Nucleosomes and Chromosomes Gene to Protein Transcription and mRNA processing Translation Mutations and Variations Synonymous, missense and non-sense mutations Genetic Engineering Making Humulin