Genetics 320/EEB320/MCB320	S1
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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)


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  • 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.


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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)


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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


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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


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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


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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”


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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)


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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)


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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


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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


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S12

Central Dogma


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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


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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)


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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….”


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All life is closely related

S16

Conservation of Cytochrome C between organisms..

Yeast PlantsWormsFlys Mice Human

Pax6 controls eye development

…in flies and humans…!!!


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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


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Gene Family: Immunoglobulin fold

S18

Proteins with similar structures evolved from single gene…and now have different functions


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S19

Model organisms and genetic techniques allow us to

figure out “Life”

(we hope)

Wildtype mutant

Model Organisms


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S20

Ultimate focus on human genetics

(.. technology provides a great assist…)


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