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Genetics 320/EEB320/MCB320 S1 Lecture 1 August 23, 2004. Ted’s Introduction Style Comments Overheads - right-hand screen Copies of figures used: Web page booklet at bookstore NOT COMPLETE!! NOR SELF-EXPLANATORY Chalkboard - ~1/5 of the presentation
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Genetics 320/EEB320/MCB320 S1 Lecture 1 August 23, 2004. Ted’s Introduction Style Comments Overheads- right-hand screen Copies of figures used: Web page booklet at bookstore NOT COMPLETE!! NOR SELF-EXPLANATORY Chalkboard- ~1/5 of the presentation Informal. Ask Questions. Stories Book-Genetics: From Genes to Genomes Hartwell et al (former colleague) 2nd edition (take your chances and responsibility with 1st edition) Problem Sets-Weekly- out Friday, due Friday By 11AM in box in front. Period. Thanks for being on time. Exams: -3 of them. Practice problems available (Ted)
Today’s Lecture: S2 Big Picture: Transmission genetics, Experimental genetics, Genomics Wed, Fri Review of basic molecular biology Preview of Experimental Genetics Chapter 1. Pages 1-12 Homework PS1 Due August 31, Friday- 10 points. Typed ONLY. • Describe ONE an interesting thing in science that you’ve heard, or that you’d like to hear more about, or that inspires you, or that puzzles you; or that scares you? • What are your career aspirations? • Name one thing you’d like to learn in genetics.
Transmission vs. Experimental GeneticsS3 Example: Genes involved in eye development in flies Mutant fly with no eyes ! Normal fly with eyes ?? Wildtype- “Gene 1+” Gene 1- (Gene 1-/Gene 1-) Transmission Genetics Question: Where are the genes? Fly cell - + - Gene 1 Fly cell + - + (2 sets of homologs shown)
Transmission Genetics vs. Experimental GeneticsS4 Example: Genes involved in eye development in flies Normal fly with eyes Mutant fly with no eyes Nothin’ Wildtype- “Gene 1+” Gene 1- (Gene 1-/Gene 1-) Experimental Genetics Ultimate Goal: Define what genes (proteins) do. Genetics Goal: Identify Genes Define order of function Define positive & negative regulators Example of Genetics Goal: Define A Pathway of Eye Development Signal Gene 1+ Gene 3+ Gene 2+ eyes And: Test specific biochemical models
S5 Use of Model Organisms in Experimental Genetics Phage Diversity in size, in genomes… ..& in what they tell us about biology. Flies Yeast Bacteria 10uM Mice
S6 Genome Comparisons- “Synteny” of mammalian genomes Human-Ape comparisons Humans/ great apes Chr 1 Chr 2 Very similar… “banding pattern” Human- Mouse Human chromosomes Wildly Sequence content Wildly mixed! Mouse chromosomes
S7 Genomics and Technology brings potential for diagnosis: Example: BRCA1, breast cancer susceptibility gene. Synthetic DNA molecules and tricks lead to the sequence of a gene… Brca1+/Brca1+ Brca1+/Brca1- • DNA sequencing of human genome: • Took several years and $millions • In<10years, your genome sequenced in 1hr for $1000!!!! • (says Lee Hood, Seattle, Wa) • Implications for disease…”priceless”
Some basic molecular biology Example: eye genes in flies S8 Normal fly with eyes Eye1* mutant no eyes Eye2* mutant multiple eyes! Genetics “make” mutants, identifies genes. A few basics about genes…. Molecular biology of a gene Genotype/phenotype/recessive/dominant Order of Function (bars and arrows)
S9 Molecular biology of a gene Eye1+ Diploid cell centromere telomere mRNA transcript E P ATG……..TGA Transcriptional regulatory sites Elements of typical gene • ORF- “Open Reading Frame”- ORF • 3 nucleotides code for amino acid. • sense TTT, TAT, ATG, etc (61) • nonsense TGA. TAA, TAG “stop” codons (3) • P -promoter, RNA polymerase binding site • E- “Enhancer” binding site; helps RNA polymerase • 5’ and 3’untranslated regions of transcript • (No introns here to simplify the discussion)
S10 • Chapter 1: Genetics: The Study of Biological Information • Key Points: • Bioinformation is in DNA • Biological function emerges mostly from proteins • Complexity in biological systems • All life is closely related • Modular construction, gene families and rapid evolution of • GENOMES • Model organisms allow us to figure out “Life” • Focus on human genetics
S11 Bioinformation: Resides first in DNA chromosomes DNA ~10 base pairs ~100 million base pairs Base-pairing Gene density • DNA- A-T, C-G base pairing: • Gene density (>50% in bacteria, ~3% in humans… • Chromosomes have wildly different sizes- • ~108bp/chromosome in humans • ~4x106bp/chromosome in bacteria
S12 Central Dogma
S13 • Bioinformation: function in proteins (mostly) • Numbers argument: • 20 amino acids in proteins • 4 bases in nucleic acids, • (and other candidate molecules - carbohydrate?) • Some enzymatic functions in RNA… • (life may have begun with RNA, in fact) Bioinformation: proteins-proteins, proteins-RNA, proteins-DNA
S14 Complexity…. Why the study of biology will continue for many decades. 1. “Mind-boggling” range of scale.. 2. More Practically: most proteins have more than one function with many functions (cytochrome C in energy and cell death)
S15 • 3rd Level of Complexity • 1 protein effects multiple complexes • (A way to understand why different alleles might have • different affects in different people) “If protein 1 is less active, then protein 1 might form less protein1-protein5 complex, which means that protein-5 dependent function is reduced, which means that….”
All life is closely related S16 Conservation of Cytochrome C between organisms.. Yeast PlantsWormsFlys Mice Human Pax6 controls eye development …in flies and humans…!!!
S17 Modular construction and gene families allows for rapid evolution of genomes What is a gene family: structurally-related proteins How they arose during evolution; gene duplication
Gene Family: Immunoglobulin fold S18 Proteins with similar structures evolved from single gene…and now have different functions
S19 Model organisms and genetic techniques allow us to figure out “Life” (we hope) Wildtype mutant Model Organisms
S20 Ultimate focus on human genetics (.. technology provides a great assist…)