Heredity and Evolution

1
Heredity and Evolution

• Chapters 1-12

• II. Heredity and Evolution (25)
• Heredity (8)1.Meiosis and gametogenesis
  2.Eukaryotic chromosomes 3.Inheritance patterns
• B. Molecular Genetics (9)1.RNA and DNA structure
  and function 2.Gene regulation 3.Mutation 4.Viral
  structure and replication 5.Nucleic acid
  technology and applications
• C. Evolutionary Biology (8)1.Early evolution of
  life 2.Evidence for evolution 3.Mechanisms of
  evolution

2
Meiosis and Gametogenesis

• Reduce chromo and increase variation
• Male gamete female gamete zygote
• Germ-line vs. somatic
• Unique features of meiosis
• Two divisions, one replication
• Synapsis, crossing over at chiasmata
• Reduction division - Anaphase I (segregation,
  indp asst)
• Meiosis I still has doubled chromosomes
• 4 haploid cells with variety
• Parthenogenesis?
• Errors -- nondisjunction aneuploidy
• Downs (Trisomy 21)
• Klinefelter, Turner, Jacob
• Amniocentesis, Chorionic Villi Sampling
• Karyotype of chromosomes only

3
Patterns of Inheritance

• Mendel and the peas (success!)
• Gene, allele, diploid, homozygous, heterozygous,
  genotype, phenotype
• Law of Segregation
• Diploid --- haploid --- zygote
• Dihybrid
• Law of Dominance
• Stronger allele, weaker allele
• Law of Independent Assortment
• No linkage?? (crossing over)
• Rr x Rr -- genotype 121, phenotype 31
• R? -- testcross
• RrSs x RrSs -- phenotype 9331
• RrSsTtUu x RRSsttUu

4
Patterns of Inheritance

• Non-Mendelian
• Codominance -- equal
• Incomplete -- blend
• Multiple alleles -- blood type
• Pleiotropic -- cystic fibrosis
• Epistasis -- two step pathway
• Environmental (nature vs. nurture)
• Continuous variation polygenic
• Sex-linked -- on X (hemop, r/g color, white eyes
  Drosophila)
• Pedigrees - ID pattern of inheritance
• Gene Diseases
• Huntingtons,Tay-Sachs (ethinicity), PKU, Cystic
  fibrosis, sickle cell, hemophilia, red-green
  colorblind

5
RNA and DNA - Structure/Function

• DNA experiments
• Griffith - transformation
• Avery and Hershey-Chase -- transforming factor
  DNA (viruses)
• Chargaff (AT, GC, of purines (AG) pyrim
  (TC)
• Franklin, Watson, Crick -- backbone,
  complimentarity, anti-parallel
• Meselson-Stahl -- semi-conservative
• DNA Structure - double strand of nucleotides
• DNA Replication
• Origin (multiple for eukary)
• Enzymes!
• Helicase
• Need primer (RNA)
• Single stranded binding proteins
• Gyrase (topoisomerase)
• Polymerases (III mainly, II is repair, I fills in
  gaps) -- synthesize 5-3, proofread
• Ligase
• Leading and lagging strand
• Okazaki fragment loops back through
• Telomeres end of chromosome, not replicated on
  lagging!

6
RNA and DNA - Structure/Function

• One gene - one polypeptide?
• Central Dogma
• DNA -- RNA -- Protein (why?)
• Gene, mRNA, tRNA, amino acid, ribosome
• Reading frame 3 letters (codon, anticodon)
• Code is universal
• AUG, UGA, UAA, UAG
• Wobble
• Transcription -- RNA Polymerase (eukary, rmt)
• Template strand (antisense), coding strand
  (sense)
• Promoter - Initiation (complex of in eukary,
  TATA)
• Elongation - synthesis in 5-3, no proofreading
• Termination
• Posttranscrip modif in eukaryotes
• 5 cap protects/initiates transl. Poly A tail -
  protect, exit)
• Alternative splicing - introns, exons, snRNPS,
  spliceosome

7
Translation

• tRNAs carry amino acids (aminoacyl-tRNA
  synthases)
• Initiation - tRNA binds to P site, A, E empty
  (complex of eukary)
• mRNA binds, large subunit binds
• Elongation, translocation, termination
• Surface of thyla has photosystems (II and I)
• (ETC) -- Energy received, split water, e-
  excited, e- transferred (loose energy when
  pumping H), energy received, e- transferred to
  NADP
• H accumulate in thylakoid space, down electro to
  make ATP
• Pro vs. eu
• Eu have introns (archae), cap and tail
• Pro have operons
• Pro simultaneous transcrip/translate
• Ribosome size (antibiotic target)
• Mutations (random, variation)
• Substitution, chemical modif, insertion,
  deletion, duplication, inversion,
• Silent, missense, nonsense

8
Gene Reg

• Transcript
• Binding motifs allow gene recognition
• Prokaryotes -- Operons
• Inducible (lac) vs repressible (tryp)
• Activators vs. repressors (both allosteric)
• Eukaryotes
• 1. packing/unpacking DNA
• 2. transcription
• 3. mRNA processing
• 4. mRNA transport
• 5. translation
• 6. protein processing
• 7. protein degradation

9
DNA Technology

• Restriction Enzymes
• Cut at restriction site
• Genetic engineering
• Vector, host
• Cleavage, Recombinant, Cloning, Screening
• Library of genes, cDNA expressed
• PCR heat, cool, copy, repeat
• Gene therapy, transgenic (agriculture --
  pesticide, herbicide, drought, N fixation
• DNA Fingerprints
• Gel electrophoresis process
• RFLP - restriction fragment length polymorphisms
• Plasmid mapping
• Gene Maps -- crossing over, microarrays
• Cloning
• Stem Cells

10
Viruses

• Envelope, Capsid and Nucleic Acid
• Envelope impt for specificity
• ss? ds? RNA? DNA?
• Retrovirus
• Reverse transcriptase enzyme
• Lytic vs Lysogenic
• Attach, insert, replicate, assemble, burst
• HIV AIDS
• RNA retrovirus, lysogenic (latent), CD4 helper T
  cells (macrophage)
• Opportunistic infections
• Influenza and vacines
• Prions and Viroids

11
Natural Selection and Evolution

• Process (Darwin and Wallace)
• ACTS ON ORGANISM/phenotype
• Inherited Variation (vs acquired Lamarck)
• Competition
• Natural Selection Force
• Reproductive Success
• Agents of Change
• Mutation, Gene Flow, Genetic Drift, Nonrandom
  mating, Selection
• Evolution acts on population
• Change in Allele Frequency
• pq 1, p22pqq21

12
Early Evolution

• Oparin, Miller/Urey
• Primordial soup (organic cmpds, no O2)
• Abiogeneisis pro/ana/hetero
• 2.5 bya
• Adaptive radiation photo, aero (form ozone)
• Endosymbiont
• Mito 1st, Chloro 2nd
• Self-replicate, own ribosomes, own DNA, own inner
  membrane
• Biogenesis

13
Evidence for Evolution

• Darwins finches
• Adaptive radiation (islands are great)
• Peppered moth (industrial melanism)
• Artificial selection (livestock, dogs)
• Fossil record
• Relative dating vs. absolute (half lives)
• Anatomy
• Homology, imperfect structures, vestigial,
  analogy
• Divergent vs convergent evolution
• BIOCHEMICAL
• Antibiotic/Pesticide today

14
Mechanisms for Evolution

• Speciation (allopatric or sympatric)
• Reproductive Isolation
• Geographic isolation (river)
• Ecological (on ground, in tree)
• Temporal (time of year)
• Behavioral (song)
• Mechanical (structures)
• Gamete Fusion
• POST Hybrid inviability or infertility
• Pace
• Gradualism (slow accum over time)
• Punctuated equilibrium (dramatic change, usually
  environmental)
• Patterns
• Directional, disruptive, stabilizing

15
Systemics and Phylogeny

• Classification
• DKPCOFGS (name genus, specie)
• Phylogenic tree
• How closely related and what order
• Common ancestor, derived traits
• Monophyletic, paraphyletic, polyphyletic
  (protists)

16
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