BIOS /30/17. DNA in the Courtroom Student Ques3ons from edx.. A Protein is a Polymer too. Week 2. Biology s Impact in Our World.

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1 Week DNA in the Courtroom Student Ques3ons from edx.. 1. STR vs VNTR, RFLP. Do police need probable cause to collect DNA samples?, how to guard against unreasonable search and seizure?. 3. What is difference between DNA sequencing vs. DNA fingerprinkng.. Do STRs allow us to determine that individuals are related. 5. DNA electrophoresis-what is mechanism? 6. CODIS- do insurance companies have access? And 1. What did you do at very end of class about making a protein? BIOS1191 Biology s Impact in Our World DNA RNA Protein protein A Protein is a Polymer too A folded and ac3ve protein side chains backbone 6/8/17 X-ray analysis on lysozyme Why do proteins fold in a par3cular way? 1

2 hvps:// s3ck and ball view of protein Ribbon view of protein Amino acid side chains: different avrac3ve/repulsive forces exis3ng between the individual amino acids allow par3cular folded proteins to be stable Jane Richardson A Protein in Ac3on Proteins recognize and interact with other cellular components. Two major classes of proteins (1) enzymes create or break down cellular components. () structural proteins are used to build cell stuff. Gene Muta3ons Compound 1 Compound 3 Compound Enzyme Converts 1 + à 3 Gene3c Disease due to Thrombin muta3on G G C G A C C T G A G C G G C G A C G T G A G C Gene<c disease sequence 6/8/17 Q. If this part of the protein made by the an3thrombin gene has the amino acid sequence: -GLY-ASP-LEU-SER- how will the nucleo3de change present in the gene3c disease version of the gene alter the protein?

3 Week : DNA in the Courtroom PCR simplifies the detec3on of STRs. basics of agarose gel electrophoresis crime forensics mitochondrial DNA human ancestry and migra3on Wednesday: merging with gene3cs Review: PCR 1 Copies of Target DNA Copies of Target DNA Cycle 1 Cycle Cycle 3 8 Cycle 16 Cycle : over 1 million! Power of PCR Human Gene<c Informa<on copies each of: 3x1 9 nucleo3de base pairs 3 chromosomes 19, genes ~75% is extra DNA separa3ng genes --new source of evidence --possible to analyze old (ancient?) DNA Gene 1 Gene Gene 3 STRs do not Alter the Genes on the Chromosome Gene 1 Gene Gene 3 Following PCR, DNA samples are separated according to their size BEFORE AFTER Video: STR summary: video on DNA size separa3on (we ll stop video at 3:13) 3

4 8/3/17 DNA analysis of evidence at crime scene and from two suspects: Why DNA in mitochondria? Wednesday Mitochondria have DNA Evidence for Endosymbio3c Theory (196s) Membranes Mitochondria have their own cell membranes, just like a prokaryo3c cell does. Endosymbiosis is the theory that freeliving cells engulfed freeliving prokaryo3c cells early in the history of life. These cells evolved into eukaryo3c cells and retain the original prokaryo3c cell as mitochondria and chloroplasts. DNA Each mitochondrion has its own circular DNA genome, like a bacteria's genome, (but much smaller). Reproduc<on Mitochondria mul3ply by pinching in half the same process used by bacteria. Predic3ons subsequently verified: Mitochondrial membranes are composed of proteins more similar to those of a prokaryo3c cell than of a eukaryo3c cell Ribosomes, and protein manufacturing systems are more similar to prokaryo3c cell than eukaryo3c cell. Endosymbiosis Many an3bio3cs that kill or inhibit bacteria also inhibit protein synthesis of mitochondria. Lynn Margulis Alfred Wegener s Con3nental Drir Theory, proposed 191, was not widely accepted un3l ~195 Key: =male =female =, = standard, = type of interest Q1. WHAT IS MODE OF INHERITANCE? A. NOT INHERITED B. RECESSIVE INHERITANCE C. DOMINANT INHERITANCE D. ONLY THROUGH FATHER E. ONLY THROUGH MOTHER

5 8/3/17 Mitochondrial DNA sequences of unrelated people possess differences Why maternal inheritance? Sperm Egg Person 1 Person Person 3 Person Egg Zygote (fer3lized egg) --Each different sequence is referred to as a haplotype. LOSE LOSE LOST LOST COST COST COAT COAT BOAT BOAT HOSE HOST HEIST GOAT 1. Determine common and differences in sequences within the sequence data Use sta3s3cal analysis to reveal the rela3onships among the sequences. Rarely a change (a muta3on) in the mitochondrial sequence will occur, this will be passed on to offspring. Sampling of mitochondrial haplotypes in the human popula3ons from around the globe. 3. Infer the branch points to account for emergence of all mitochondrial sequences. Tree shows relatedness, how many branches=steps needed to get from one to another. 5

6 8/3/17 The diagram depicts that the mitochondrial DNA diversity in human popula3ons is consistent with a set of migra3ons across the planet. The numbers shown are es3mate of how many years ago the migra3ons took place. 1. Basic rule of Mendelian gene3cs is that individuals have two copies of all genes and will pass one of these two copies to their progeny. A paternity case: What do the results here say about this man being the biological father? Work Groups Mendelian gene3cs à STRs are present on chromosomes are thus are inherited in the same way as genes. Useful in legal system to determine paternity. hvps://drive.google.com/a/nd.edu/file/d/b-po7pzihfp7zk1bjd5rvhdou/view?usp=sharing Q3. Are the results consistent with the parents being the biological parents of the son? YES NO Q. Are results consistent with the parents being the biological parents of the daughter? YES NO Q5. Maternal or paternal grandparents? (Is it the paternal grandparents or the maternal grandparents included in the analysis?) MATERNAL PATERNAL Dominant vs. Recessive Mendel s peas S = makes an ac3ve protein that performs role in plant cells that makes the pea seed smooth. S = a mutant form of the protein that is defec3ve and unable to make the pea seed become smooth. In a heterozgote (S / S), why is the pea smooth? Can you imagine a different result? 6

7 C / C Wrapping Up c / c A temperature sensi3ve version of C: ac3ve at low temperature, inac3ve at higher (body) temperatures. Q6. Does a Siamese cat get darker or lighter during the summer? Ques3ons? Our major points of week : STRs exist within individual chromosomes STRs are readily detected by PCR. Basics of separa3ng DNA by size. Analyzing DNA for crime forensics Mitochondrial DNA, human ancestry and migra3on Mendelian gene3cs (gene inheritance) DNA tests in paternity cases Understanding recessive and dominant inheritance for Friday: Class meets at DNA Learning Center Rm. 139 Jordan Hall Gene<c Basis of Tas<ng Phenylthiocarbamide As her DNA tests predicted, this student certainly could taste a biver substance called phenylthiocarbanide The gene3c taste phenomenon of PTC was discovered in 1931 when a DuPont chemist named Arthur Fox accidentally released a cloud of a fine crystalline PTC. A nearby colleague complained about the biver taste, while Fox, who was closer and should have received a strong dose, tasted nothing. 7