Genetics: The Old and the New (and there is a “Lot” of Newness) Introduction Introduction...
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Transcript of Genetics: The Old and the New (and there is a “Lot” of Newness) Introduction Introduction...
Genetics: The Old and the Genetics: The Old and the New New
(and there is a “Lot” of (and there is a “Lot” of Newness)Newness)
IntroductionIntroduction Analogy to an “information Analogy to an “information
broker”broker” Radical transformation of the Radical transformation of the
science (i.e., science (i.e., what is a revolution what is a revolution in the sciencesin the sciences))
Genetics of inheritance - Genetics of inheritance - Mendelian geneticsMendelian genetics ( (>> 1860) 1860)
Genetics of cell’s operation - Genetics of cell’s operation - molecular geneticsmolecular genetics ( (>> 1950) 1950)
The “Genetic Code”The “Genetic Code” Genetics “on the cutting edge”: Genetics “on the cutting edge”:
last five yearslast five years
IntroductionIntroduction
Why is an “information broker” Why is an “information broker” important in living systems?important in living systems?
What constitutes a “revolution” What constitutes a “revolution” in the sciences?in the sciences?
The Old: Genetics of The Old: Genetics of Inheritance (Inheritance (1860’s1860’s))
Classical or Mendelian genetics (Gregory Mendel)Classical or Mendelian genetics (Gregory Mendel) Competing Competing hypotheseshypotheses
Blended inheritance versus particulate inheritanceBlended inheritance versus particulate inheritance Testing the hypotheses (Scientific Method!!)Testing the hypotheses (Scientific Method!!)
Flower color in peas (1 parent with red flowers and 2Flower color in peas (1 parent with red flowers and 2ndnd parent parent with white flowers)with white flowers)
Results: two classes of flowersResults: two classes of flowers Red (300 seedlings)Red (300 seedlings) White (100 seedlings)White (100 seedlings) Pink (0 seedlings)Pink (0 seedlings)
ConclusionConclusion Hypothesis: Hypothesis: Data support the particulate theory Data support the particulate theory
Data reject blended Data reject blended theorytheory
Specific quantitative data: Specific quantitative data: 3:1 ratio 3:1 ratio (strange but revealing (strange but revealing quantitative quantitative ratio!)ratio!)
300 100
Rules of Classical Rules of Classical Mendelian Genetics Mendelian Genetics
(1860’s)(1860’s) Traits passed from parent to offspring Traits passed from parent to offspring
consistent with particulate inheritance consistent with particulate inheritance modelmodel Mechanism unknown at the time (now we know)Mechanism unknown at the time (now we know)
Two “copies” of each trait in each individualTwo “copies” of each trait in each individual One from each parentOne from each parent
Some “copies” are dominant and some Some “copies” are dominant and some copies are recessivecopies are recessive Dominant traits = expressedDominant traits = expressed Recessive traits = expressed only if both copies Recessive traits = expressed only if both copies
recessiverecessive
Mendelian Genetics Mendelian Genetics (1860’s) and Coming (1860’s) and Coming
ForwardForward GeneGene - trait determined by a sequence of DNA - trait determined by a sequence of DNA AlleleAllele - alternative forms (“ - alternative forms (“copiescopies”) of the same ”) of the same
gene (e.g., normal hemoglobin vs sickle cell gene (e.g., normal hemoglobin vs sickle cell hemoglobin; blue vs brown eyes)hemoglobin; blue vs brown eyes) No longer called “copies” but alleles!!!No longer called “copies” but alleles!!!
Dominant alleleDominant allele (e.g., brown eyes) (e.g., brown eyes) Recessive alleleRecessive allele (e.g., blue eyes) (e.g., blue eyes) ChromosomesChromosomes - physical packaging of genes in - physical packaging of genes in
nucleusnucleus Pairs of chromosomesPairs of chromosomes GenomeGenome - all of the genes of an organism in the - all of the genes of an organism in the
nucleusnucleus
QuestionQuestion
If you were to cross rabbits that were black with rabbits that were white and the offspring were gray, this outcome would support the theory of ___________.
A particulate inheritanceB conspicuous inheritanceC Lamarckian inheritanceD blended inheritanceE None of the above
QuestionQuestion
The “unit of inheritance” documented by Mendel is now called the ___.
A hybridB parental strainC geneD dominant alleleE the “Mendel”
QuestionQuestion
In genetic crosses the re-current quantitative ratio of 3:1 among offspring supports the presence of ____ copy/copies of each gene in an organism of all species of eukaryotes.
A fourB threeC two D one
Genes and ChromosomesGenes and Chromosomes
DNA to Genes to DNA to Genes to ChromosomesChromosomes
Gene
Chromosomes, Genes Chromosomes, Genes and Allelesand Alleles
Hemoglobin Chemistry
Ear Lobe
Eye Color
Blood Group
Individual One (Thee)
Individual Two (Me)
A O OB
Blue
Brown
Blue
Blue
Attached
Attached
Free
Free
Normal
Normal
Normal
Sickle Cell
Genetics of Humans: Sex Genetics of Humans: Sex DeterminationDetermination
Humans = 46 chromosomes or 23 pairsHumans = 46 chromosomes or 23 pairs Sex determination associated with one Sex determination associated with one
pair of chromosomes (Pair No. 21)pair of chromosomes (Pair No. 21) X and Y chromosomeX and Y chromosome
Female: two “X” chromosomesFemale: two “X” chromosomes Male: one “X” and one “Y” chromosomeMale: one “X” and one “Y” chromosome Female produces only X chromosome Female produces only X chromosome
eggseggs Male produces both X and Y Male produces both X and Y
chromosome spermchromosome sperm
Who determines the sex of offspring? Who determines the sex of offspring? Sex-linked traits … examples?Sex-linked traits … examples?
Complexity of the Human Genome
46 chromosomes in each human (23 pairs)
~20,000 different genes in each human
Only ~1.5% of genome active
… we think (stay tuned!)
Millions of nucleotide differences between any two people
Affymetrix
Genetics: The Old and the Genetics: The Old and the NewNew
IntroductionIntroduction Analogy to an “information Analogy to an “information
broker”broker” Radical transformation of the Radical transformation of the
science (i.e., revolution)science (i.e., revolution) Genetics of inheritance - Genetics of inheritance -
Mendelian genetics (Mendelian genetics (>> 1860) 1860) Genetics of cell’s operation - Genetics of cell’s operation -
molecular genetics (molecular genetics (>> 1950) 1950) The “Genetic Code”The “Genetic Code” Genetics “on the cutting edge” Genetics “on the cutting edge”
((>> 2005) 2005)
Molecular GeneticsMolecular Genetics Structure of DNA Structure of DNA and RNA and RNA - -
information storage, information storage, transmission and expressiontransmission and expression
ReplicationReplication of the of the information - information - copying/duplication copying/duplication
TranscriptionTranscription of the of the information - transcribing information - transcribing
TranslationTranslation of the of the information - expressing as information - expressing as proteins (requires new proteins (requires new language with new language with new alphabet!)alphabet!)
Watson and Crick: Watson and Crick: a Revolution in the a Revolution in the
SciencesSciences
1953
Double helix
Watson Crick
Contribution of Watson and Crick: Monomer = Nucleotides (A, T, C and G) Polymer = polynucleotide (nucleic acid) 3 D Structure of Nucleic Acid = DNA Double Helix
Nucleotides: The Building Nucleotides: The Building Blocks of Nucleic AcidsBlocks of Nucleic Acids
Nucleotide: three Nucleotide: three componentscomponents SugarSugar
DNA: deoxyriboseDNA: deoxyribose RNA: riboseRNA: ribose
Phosphate groupPhosphate group
Base (N=4)Base (N=4) Adenine (A)Adenine (A) Guanine (G)Guanine (G) Cytosine (C)Cytosine (C) Thymine (T) Thymine (T)
DNA DNA StructureStructure
Join nucleotidesJoin nucleotides Alternating phosphate Alternating phosphate
and sugarand sugar DNADNA
2 strands of nucleotides2 strands of nucleotides Joined by nitrogen base Joined by nitrogen base
pairs (A, T, C and G)pairs (A, T, C and G) Bonding pattern Bonding pattern
((fidelity!fidelity!)) Adenine : ThymineAdenine : Thymine Cytosine : GuanineCytosine : Guanine
Information broker - Information broker - “biological alphabet” “biological alphabet” (A,T,C and G)(A,T,C and G)
QuestionQuestion
Nucleic acids such as DNA and RNA are polymers (macromolecules) of the monomers called ____.
A amino acidsB monosaccharidesC nucleotidesD lipids
QuestionQuestion
While the English alphabet contains 26 letters, the biological alphabet of the DNA is based on ___ nucleotides/”letters”.
A 2B 4C 6D 8
QuestionQuestion
The term “fidelity” in base pairing of nucleotides in DNA means that the nucleotide thymine always pairs with nucleotide ___.
A europocilB cytosineC another thymineD guanineE adenine
Genetics: The Old and the Genetics: The Old and the New New
(and there is a “Lot” of (and there is a “Lot” of Newness)Newness)
IntroductionIntroduction Analogy to an “information Analogy to an “information
broker”broker” Radical transformation of the Radical transformation of the
science (i.e., science (i.e., what is a revolution what is a revolution in the sciencesin the sciences))
Genetics of inheritance - Genetics of inheritance - Mendelian geneticsMendelian genetics ( (>> 1860) 1860)
Genetics of cell’s operation - Genetics of cell’s operation - molecular geneticsmolecular genetics ( (>> 1950) 1950)
The “Genetic Code”The “Genetic Code” Genetics “on the cutting edge”: Genetics “on the cutting edge”:
last five yearslast five years
Molecular Genetics: General Theme
Molecular Genetics: Structure Molecular Genetics: Structure of DNA and RNAof DNA and RNA
DNA - Deoxyribonucleic acidDNA - Deoxyribonucleic acid (nucleus; (nucleus; double stranddouble strand))
RNA - Ribonucleic acidRNA - Ribonucleic acid (protoplasm; (protoplasm; single strandsingle strand))
Monomer - nucleotides (N = 4 Monomer - nucleotides (N = 4 in DNA)in DNA) GuanineGuanine (always binds to Cytosine - (always binds to Cytosine - G:CG:C)) AdenineAdenine (always binds to Thymine - (always binds to Thymine - A:TA:T)) CytosineCytosine (always binds to Guanine - (always binds to Guanine - C:GC:G)) ThymineThymine (always binds to Adenine - (always binds to Adenine - A:TA:T))
Polymer - Polymer - polynucleotidepolynucleotide (DNA (DNA & RNA)& RNA)
Sequence of Nucleotides Sequence of Nucleotides and Genesand Genes
Linear sequences of nucleotidesLinear sequences of nucleotides
GeneGene: sequence of nucleotides responsible : sequence of nucleotides responsible for a specific trait (e.g., eye color; for a specific trait (e.g., eye color; hemoglobin; attached ear lobes, carbon hemoglobin; attached ear lobes, carbon metabolism, sickle cell anemia, enzyme)metabolism, sickle cell anemia, enzyme)
1150
102
1225
954
431
1580
653
Number of nucleotides
Molecular Genetics: A Molecular Genetics: A Single GeneSingle Gene
ExactExact sequence of nucleotides is important sequence of nucleotides is important
Any change in sequence changes the information Any change in sequence changes the information (“(“RRAT to AT to CCAT”) and constitutes a AT”) and constitutes a mutationmutation
Daily: you experience 10,000’s of mutations but all Daily: you experience 10,000’s of mutations but all are correctedare corrected
A T T A G C G G T A T G C C G G T T A A G A T C C G
A T T A G C G G T A C G C C G G T T A A G A T C C G
Molecular Genetics: General Theme
Replication
Molecular Genetics: Molecular Genetics: ReplicationReplication
ReplicationReplication:: process of process of duplicating duplicating DNA to DNA to produce a new produce a new and exact copy and exact copy with with fidelityfidelity includes “includes “spell spell
checkingchecking””
Molecular Genetics
Molecular Genetics: Molecular Genetics: TranscriptionTranscription
Information in DNA Information in DNA “transcribed” “transcribed” into into another type of message - another type of message - mRNAmRNA (messenger RNA)(messenger RNA) Analogue to transcribing spoken into Analogue to transcribing spoken into
written languagewritten language
mRNA made in nucleus and mRNA made in nucleus and subsequently shuttled to protoplasmsubsequently shuttled to protoplasm
In protoplasm, mRNA to the In protoplasm, mRNA to the ribosomeribosome (protein synthesis)(protein synthesis)
Compartmentation: Ribosome
23-494Figure 23.22
Molecular Genetics:
Translation in the Ribosome
Molecular Genetics: Molecular Genetics: TranslationTranslation
Information in mRNA “translated” into Information in mRNA “translated” into polypeptide and then functional protein and then functional protein (new language and “new letters of the (new language and “new letters of the alphabet”!)alphabet”!) Monomer: amino acids (e.g., lab exercise)Monomer: amino acids (e.g., lab exercise) Location: ribosome for protein synthesisLocation: ribosome for protein synthesis
Genetic codeGenetic code: specificity and : specificity and fidelityfidelity All organisms and all species use the exact All organisms and all species use the exact
same processsame process Example: genetically modified organisms Example: genetically modified organisms
(GMO’s)(GMO’s)
Protein Synthesis and Protein Synthesis and Genetic CodeGenetic Code
One gene codes for one proteinOne gene codes for one protein
Protein drives chemical process in cell (e.g., Protein drives chemical process in cell (e.g., enzymes)enzymes)
Original source of information = DNAOriginal source of information = DNA Intermediate source of information = RNAIntermediate source of information = RNA All living things on Earth use the absolute same All living things on Earth use the absolute same
genetic codegenetic code
Transcription, Translation Transcription, Translation and Protein Assemblyand Protein Assembly
http://www.youtube.com/watch?http://www.youtube.com/watch?v=983lhh20rGYv=983lhh20rGY
QuestionQuestion
In the following figure, the process linking the DNA to RNA (see white arrow) is called _______.
A replicationB transcriptionC translationD gene splicing
QuestionQuestion
Making a copy of DNA is called ___.
A replicationB transcriptionC translationD. photocopying
QuestionQuestion
The sum of all information contained in your DNA and copied in each cell in your body is called your ___.
A gene baseB gene traitsC genomeD. genetic material
Mutations and DNA Mutations and DNA RepairRepair
MutationsMutations Change in sequence of Change in sequence of nucleotidesnucleotides in DNA in DNA Causes of mutationsCauses of mutations
Oxygen (e.g., aging)Oxygen (e.g., aging) Nuclear radiationNuclear radiation X-raysX-rays UV light (e.g., beach time!)UV light (e.g., beach time!) Higher elevations (e.g., mountain tops, airplanes)Higher elevations (e.g., mountain tops, airplanes)
DNA RepairDNA Repair 10,000 ‘hits’ per day (you and me!!)10,000 ‘hits’ per day (you and me!!) Cells repair damage - Cells repair damage - excision and repairexcision and repair
processprocess Repair not equal in all individualsRepair not equal in all individuals
Molecular Genetics: A Molecular Genetics: A Single Gene (Single Strand)Single Gene (Single Strand) ExactExact sequence of nucleotides is important sequence of nucleotides is important
Any change in sequence changes the information Any change in sequence changes the information (“(“RRAT to AT to CCAT”) and constitutes a AT”) and constitutes a mutationmutation
Excision and repairExcision and repair
A T T A G C G G T A T G C C G G T T A A G A T C C G
A T T A G C G G T A C G C C G G T T A A G A T C C G
Genetics: The Old and the Genetics: The Old and the NewNew
IntroductionIntroduction Information brokerInformation broker Radical transformation of the science (i.e., Radical transformation of the science (i.e.,
revolution)revolution) Genetics of inheritance - Mendelian genetics Genetics of inheritance - Mendelian genetics
((> > 1860)1860) Genetics of cell’s operation - molecular Genetics of cell’s operation - molecular
genetics (genetics (>> 1950) 1950) The “Genetic Code”The “Genetic Code” Genetics “on the cutting edge” (last five Genetics “on the cutting edge” (last five
years)years)
Genetics “on the Cutting Genetics “on the Cutting Edge”Edge”
Genetic counseling (probability of offspring with Genetic counseling (probability of offspring with particular traits)particular traits)
Forensic sciences (e.g., CSI TV series)Forensic sciences (e.g., CSI TV series) Genetic engineering : Genetic engineering : GMO’s (Genetically Modified GMO’s (Genetically Modified
Organisms)Organisms) Genetic “Sleuthing”Genetic “Sleuthing”
Human applications (e.g., ice man in the Alps Human applications (e.g., ice man in the Alps ++ 5,000 5,000 years)years)
Genetic basis of autismGenetic basis of autism Genetics, mutations and cancer (next week’s Genetics, mutations and cancer (next week’s
lecture)lecture) Editing of genesEditing of genes
Genetic Counseling
Genetic Counseling using “Gene Chips”
Forensic SciencesForensic Sciences
Genetics “on the Cutting Genetics “on the Cutting Edge”Edge”
Genetic counseling (probability of offspring with Genetic counseling (probability of offspring with particular traits)particular traits)
Forensic sciences (e.g., CSI TV series)Forensic sciences (e.g., CSI TV series) Genetic engineering (e.g., “starlight” strain of Genetic engineering (e.g., “starlight” strain of
corn)corn) GMO’s (Genetically Modified Organisms)GMO’s (Genetically Modified Organisms)
Genetic “Sleuthing”Genetic “Sleuthing” Human applications (e.g., ice man in the Alps Human applications (e.g., ice man in the Alps ++ 5,000 5,000
years)years) Genetic basis of autismGenetic basis of autism Genetics, mutations and cancer (next week’s Genetics, mutations and cancer (next week’s
lecture)lecture) Editing of genesEditing of genes