Presentation on theme: "Announcements 1. Genetics-related course offerings for spring 2003:"— Presentation transcript:
1Announcements 1. Genetics-related course offerings for spring 2003: - BIO 324 Cell biology, 3 credits; 3 hours in lecture- BIO 325 Biotechnology, 3 credits; 5 hours in lab-BIO 397 Seminar in Human gene therapy, 1 credit-BIO 403 Undergraduate Research, 3-4 credits; needs to be arranged one semester in advance with faculty-BIO 597Q Confocal microscopy, 4 credits-BIO 597Y Techniques in molecular biology, 3 credits; 3 hours in lecture - no lab.-BIO 620G Conservation Genetics, 3 credits; lecture and lab-BIO 629B Eukaryotic Molecular Genetics seminar, 1 credit2. Ch 10: problems 1,4,13, 15 - not to turn in
2Restriction Digest Lab: Use This Gel! Start measuringfrom here.Lanes1 - Markers2 - Uncut plasmid3 - EcoRI cut4 - DraI cut5 - EcoRI + DraIMolecular weightmarkers in bp3 real bands2 real bandsSupercoiled form runsfaster, nicked form runsslower than linearizedplasmid.Bright band is cut;faint band is uncut
3Review of Last Lecture I. Sry and sex determination II. Dosage compensation - different in humans and fliesIII. NondisjunctionMonosomyTrisomy
4Outline of Lecture 18 Polyploidy Variation in structure/arrangement of chromosomes- deletion- duplication- inversion- translocationIII. DNA structure and analysis
5I. Polyploidy Hybridization of closely related species; often sterile. Additional sets identical to parents.
6How does polyploidy arise naturally How does polyploidy arise naturally? - DNA is duplicated in S phase but cell doesn’t go into M phase - Generation of Tetraploids Using Colchicine, a Microtubule InhibitorTriploids can be created by inhibition of polar bodyformation during oogenesis, followed by fertilization.
7How is polyploidy relevant to our daily lives? Polyploids are generally bigger than diploids;therefore, in horticulture and agriculture they are useful.Examples: -Bananas and tiger lilly - 3n-coffee, peanuts, McIntosh apples - 4n-strawberry - 8n
8Somatic Cell Hybridization in Plants creates Allopolyploid Hybrids American Cotton is natural hybrid
9II. Types of Chromosomal Rearrangements, Caused by Breakage and Rejoining
10Deletions Chromsome breaks Part is lost - a deletion Synapsis with a chromosomewith a large intercalary deletion - loop formation.
11Duplications Cytology showed that bar is not due to a gene mutation. Gene redundancyPhenotypic variationSource of genetic variation during evolutionUnequal crossing over
12Ohno’s hypothesis on the role of gene duplication in evolution Question: How do “new” genes arise?Duplications might allow for major mutation in the extra copy of the gene. Over time, mutations could result in a new function for the duplicated gene - essentially a new gene.Example: myoglobin and hemoglobin
13InversionsInversions don’t add or delete genetic info, but can have effects on gamete formation.
14Translocations Robertsonian translocation: most common type in humans One example:SRY in an XX “male”
15Inheritance of 14/21 Translocation In Families with Down Syndrome
16Familial Down Syndrome Patient with 14/21 Translocation/21 14
17Learning checkWhat types of chromosome mutations are required to change this chromosome into each of the following?A B C D E F GA B A B C D E F Ga. inversion of A Bb. deletion of A Bc. duplication of A BA B E D C F Ga. translocation of C D Eb. inversion of C D Ec. deletion of C D EOO
18Learning check #2A species has 2n = 16 chromosomes. How many chromosomes will be found per cell in each of the following mutants in this species?MonosomicAutotriploidTrisomicAutotetraploid15241732
19III. DNA Structure and analysis What is the genetic material?Chromosomes contain protein and DNA - which is it?What must genetic material do?1. Replication2. Storage of information3. Expression of information4. Variation by mutation - evolution
20The Flow of Genetic Information (The Central Dogma) Trait
21Is the Genetic Material Protein or DNA? Many favored proteins until the mid-1940’s.DNA is simple chemically; how could it then hold complex genetic information?Proteins are much more complicated chemically; perhaps they might hold genetic information.
22Evidence for DNA as Hereditary Molecule Transformation studiesGriffith (1927)Avery, MacLeod and McCarty (1944)Hershey-Chase experiment (1952)Chargaff’s RulesMolecular Studies
24Avery, MacLeod, and McCarty Expt: DNA is the “Transforming Principle”
25Hershey-Chase Experiment Radioactively labeled DNA and protein:32P atom is in phosphate molecules in DNA and RNA, only low levels in protein (phosphorylated proteins).35S atom is in sulfur containing-amino acids (cysteine and methionine), not in DNA, RNA.
26Phage Made Radioactive Non-radioactive medium+ bacteria
31Bases and Sugars in DNA and RNA In DNA: deoxyribose + A, T, G or CdA deoxyadenosinedT deoxythymidinedG deoxyguanosinedC deoxycytidineIn RNA: ribose + A, U, G, or CA adenosineU uridineG guanosineC cytidine
33dNDP’s and dNTP’s: Note Errors in the Text deoxydeoxydeoxydeoxydNDP (dTDP)dNTP (dATP)
343’ to 5’ Phosphodiester Bonds Make the Sugar-Phosphate Backbone New MonomersAdd HereStrand has 5’-PO4end and 3’-OH end
35Chargaff’s Rules, quantified amounts of each base in DNA from different species.In every species, amount of A = Amount of T, and Amount of G = Amount of CIf that’s true, then A + G = C + TThe % GC and % AT varied from species to species, but always adds up to 100%.