59 th Medical Wing Providing Great Care – Building Warrior Medics! Molecular Diagnostics for Dummies Capt G. Shane Hendricks, USAF, BSC, MS, MT (ASCP) Associate Chief, Diagnostic Services 59th Laboratory Squadron

Providing Great Care… Building Warrior Medics! Foreword Brief history and basic molecular genetics concepts Mendel to Watson-Crick Central Dogma Molecular techniques - clinical and research PCR REs/Gels/RMs Blots Etc. Example applications within clinical laboratory

Providing Great Care… Building Warrior Medics! Brief History and Basics

Providing Great Care… Building Warrior Medics! History of Genetics Mendelian Genetics Gregor Mendel Crossed pea plants w/ varied traits Proved trait inheritance What was the biochemical basis of traits? 4 properties apparent: copied, stored, expressed, changed Prior to protein More abundant DNA thought too simple

Providing Great Care… Building Warrior Medics! History of Genetics DNA first isolated in Friedrich Miescher Called material “nuclein” (came from nucleus) Phoebus Levene in 1919 Identified nucleotide units Base, sugar, phosphate components Believed repeating; too simple for genetic information ATGC First proof of genetic material - transformation Griffith

Providing Great Care… Building Warrior Medics! Griffith

Providing Great Care… Building Warrior Medics! What was transforming factor? Avery, McLeod, McCarty Used “cell-free” system Factor was called DNA

Providing Great Care… Building Warrior Medics! Contribution of Viruses Hershey, Chase Used bacteriophages Used radioactive isotopes of Phosphorus/Sulfur

Providing Great Care… Building Warrior Medics! What about Eukaryotes? Indirect evidence Haploid cells - 1/2 material of diploid cells Mutagenesis nm mutate material, not protein Proteins absorb at 280 nm Direct evidence Transfection - material introduced into cells; new trait acquisition

Providing Great Care… Building Warrior Medics! Structure of DNA Many genetic pioneers found puzzle pieces William Astbury Rosalind Franklin James Watson, Francis Crick Put pieces together! Built first accurate model

Providing Great Care… Building Warrior Medics! Structure of DNA (cont.) Two polynucleotide chains in double helix Each chain associates by hydrogen bonding A:T (2 bonds), G:C (3 bonds) Chains run anti-parallel Sense - equivalent to mRNA transcript Anti-sense - “compliments” Sense strand Sugar-phosphate backbone outside Bases lie flat inside, perpendicular to central axis Grooves

Providing Great Care… Building Warrior Medics! Structure of DNA (cont.)

Nucleobases: Purines pyrimidines Nucleobases: Purines pyrimidines } } Nucleoside NTP = ATP, GTP, etc.

Providing Great Care… Building Warrior Medics! Nuts and Bolts Biomolecular polymers and information Nucleic acids (DNA and RNA) store information Quaternary variation 2n2n 4n4n

Providing Great Care… Building Warrior Medics! Nuts and Bolts (cont.) Stored information transcribed first Transcript next translated into peptides Oligopeptides  polypeptides  protein Variety of structural and/or catalytic functions

Central Dogma ???

Providing Great Care… Building Warrior Medics! More Basics (cont.) Gene - discrete sequence Genome - all genetic information Expression Regulation - off or on? Promoters - upstream Complex in eukaryotes TATAAA Regulation-associated pathology Asthma Beta thalassemia Various cancers Chimeric proteins - e.g., Philadelphia Chromosome (CML)

Providing Great Care… Building Warrior Medics! Eukaryotic Chromosomes Chromatid

Providing Great Care… Building Warrior Medics! Eukaryotes (cont.)

Providing Great Care… Building Warrior Medics! Eukaryotes (cont.) Haploid vs. Diploid Homo- vs. Heterozygous Dominant and Recessive Phenotype vs. Genotype P P Pp PPPPp p pp p p

Providing Great Care… Building Warrior Medics! Prokaryotic Chromosomes

Providing Great Care… Building Warrior Medics! Prokaryotes (cont.)

Providing Great Care… Building Warrior Medics! Prokaryotes (cont.)

Providing Great Care… Building Warrior Medics! Replication

Providing Great Care… Building Warrior Medics! Replication Mitosis, meiosis Faithful DNA reproduction Theories Dispersive Conservative Semi-conservative

Replication (cont.)