Uplift Education



Serology & DNA Guided NotesName: _____________________________3177540952500What is blood made of?________________________Contain hemoglobinTransport O2___________________________Produce antibodies, attack and digest pathogens51943001524000____________________________Repair broken blood vessels and form of clots__________________________Water and dissolved chemicals (food, waste, etc.) IDENTIFYING BLOOD STAINSA __________________________________ is a test that lets you know that a certain substance (i.e. blood) may be present. A negative result = ____________________________________________A positive result = _____________________________________________, or a different substance may be causing the positive resultIf investigators get a positive result with a presumptive test, they will usually be fairly confident that blood is present – but they will need to do more tests to prove it in court.Nearly any test has some chance of providing the wrong result. Medical tests are often discussed in terms of rates of false positives and false negatives.at-home pregnancy testvery low rate of false positive a positive result means you are almost certainly pregnanthigh rate of false negative if taken earlyif you get a negative result you should retest in a few days.A mammogramlow rate of false negativeAbnormal breast tissue is easily identifiedhigh rate of false positives only some abnormalities are cancerous.Do presumptive tests have high false negatives or high false positives?Catalytic Color Tests704850250825Catalyst – Oxidation – 020000Catalyst – Oxidation – The hemoglobin in blood acts like a _____________________ for some _______________________ reactions.Many versions of these tests but all involve a _______________________ when blood is presentOne common test uses ______________________________. For ease of field use, this reagent can be put on strips of paper (_____________________) that can be moistened with distilled water then toughed to a stain. If the stain has blood, the strip will turn green.Causes of misleading resultsFalse negatives: a stain that has been cleaned with bleach will often not reactFalse positives: some vegetables, including potatoes and horseradishAre catalytic color tests presumptive? Why or why not?Luminol and BluestarUses __________________________________ – the emission of light from a chemical reaction – to identify bloodSprayed over an area with suspected stains; blood will light up; investigators will photographVery sensitive – can detect blood that has been washed away / diluted to 1 part per 5,000,000 Luminol is visible only in a fairly dark room; Bluestar can be seen under normal lightingCauses of misleading resultsFew false negativesFalse positives: bleach, metals, plasterIs luminol a presumptive test? Why or why not?Microcrystalline testsFormation of crystals from the heme groups of hemoglobin__________________________________________ – very low incidence of false positivesDoes cause some false negatives – can be a difficult procedure to master If crystal tests are confirmatory, why do presumptive tests?Collection and Handling of Blood EvidenceCollecting from a liquid stain/pool of blood Dip a ____________________________ into each stain Allow swabs to _____________________________Collecting dried blood When possible, collect the entire stained object (e.g. piece of clothing)If not possible to collect entire object then investigators may cut out the stain (e.g. from car upholstery) OR may moisten the stain with distilled water and then collect on cotton swabsOther bodily fluids (e.g. semen) are collected and packaged in a similar fashionRemember! All biological materials should be packaged in paper bags / envelops, NOT plasticPPE (personal safety equipment) is essential during collection!Blood FactorsBlood factors are _______________________________________________________More than 250 different blood factors!Some blood factors are also _______________________________________________________ ______________________________________________________________________________The blood factors that cause the greatest immune response belong to the ABO and Rh groups.Antigen – Antibody ReactionsAntigens are foreign substances that provoke an immune response – usually the release of __________________________________________________________________________Where are they found?Surface of pathogens (e.g. viruses, bacteria, etc.)Vaccines (that’s why they work!)Allergens (e.g. pollen, dust, etc.)Cancer cells (foreign b/c cell has mutated)Transplanted tissue / organs__________________________________________ produced by white blood cells _______________________________________________. Antibodies are specific to certain antigensAgglutination313372519050When antibodies bind to RBCs, they cause _______________________, or clumpingWhy is this bad?Initially, clumps clog small capillaries, causing pain and reduced blood flowLater, RBCs that are bound to the antibodies _______________or break open, releasing hemoglobin into the blood – which can cause kidney failure4000020000When antibodies bind to RBCs, they cause _______________________, or clumpingWhy is this bad?Initially, clumps clog small capillaries, causing pain and reduced blood flowLater, RBCs that are bound to the antibodies _______________or break open, releasing hemoglobin into the blood – which can cause kidney failureABO blood groupIn the ABO blood group, there are two antigens, “A” and “B”, found on the surface of RBCsYou can have one type of antigen, both types, or neitherYou develop antibodies to the type of antigens you don’t have during infancyDetermine whether each statement is correct as written. If it is not correct, re-write it.The “A” and “B” antigens are examples of blood factors.If you have type “B” blood then you have “B” antibodies.If you have type “AB” blood then you have “O” antibodies.For people who have allergies, pollen is an antibody.Agglutination occurs when antibodies bind to the antigens in blood.Antibodies are found on the surface of red blood cells.The key to transfusions: ________________________________________________________________________________ ________________________________________________________________________________Blood TypeCan donate toCan receive fromABABOWhich type is the universal donor? Which type is the universal recipient?Rh Blood GroupThe Rh blood group describes ~45 different (but similar) antigens on RBCs. These antigens are called antigen “D”People are Rh + if they have any of the various D antigens. They are Rh – if the do not have any D antigens.Blood TypeCan donate toCan receive fromRh+Rh-With this added group in mind, what is the true universal donor? … and the true universal recipient?Blood Type Transfusion Practice1) To which type(s) can an A+ person donate blood?2) From which type(s) can a AB- person receive blood?3) To which types(s) can a B- person donate blood (?)4) From which type(s) can a O+ person receive blood?5) To which type(s) can a AB+ person donate blood?6) From which types can a A+ person receive blood?Blood Typing3276600752475__________________________ is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occursWhat does an agglutination reaction with a certain antiserum mean?4000020000__________________________ is a solution that contains antibodies against a specific antigen (i.e. antiserum A contains type A antibodies). Blood type is determined by adding antiserum A, B, and D to blood and observing whether or not agglutination occursWhat does an agglutination reaction with a certain antiserum mean?How is blood typing used in forensics?Would blood type alone be more useful for excluding or linking suspects to a crime scene? Why?Case StudySomeone broke into the house of a teenaged girl and raped her. Her injuries caused her to bleed. Her injuries caused her to bleed. The girl reported the crime as soon as the assailant left. She did not have her glasses on during the attack, and was only able to give a very general description of the assailant.The police found a man wandering the neighborhood who matched the general description and had blood on his jeans. The man claimed the stains were from a bloody nose his girlfriend’s daughter had earlier in the day3689985347980What conclusion(s) can you make based on ABO type alone? What can you conclude when you analyze additional blood factors?400000What conclusion(s) can you make based on ABO type alone? What can you conclude when you analyze additional blood factors?Blood SourceABOPGMEAPHpStains on suspect’s jeansASuspectAGirlfriend’s daughterOVictimAHow do you calculate probability?You roll one die and flip a coin. What is the probability that you roll a 3 and flip a heads?To calculate the probability of multiple _____________________________events, you ________________ the probability of each event occurring individually.Probabilities of Blood FactorsABO groupFrequency of subtypePGM groupFrequency of subtypeEAP groupFrequency of subtypeHp groupFrequency of subtypeA40%1-1.8%A11.2%116.5%B10%1+40.7%B39.5%235.0%O45%1+1-17.1%BA41.4%2-147.9%AB5%2+3.1%C0.2%????2-0.3%CA3.2%????2+2-1.9%CB4.6%????1+2+22.3%??????1-2+4.7%??????1+2-6.8%??????1-2-1.4%????What is the frequency of ABO O, PGM 1+2+, and Hp 2?What is the frequency of ABO B, PGM 1+1-, EAP CB, and Hp 1?Do Nowleft13970Genetics RefresherWe have two versions – or ______________________ – of every gene. One inherited from our mom, one from our dad.The two alleles (_______________________) interact to determine our trait (____________________) in predictable ways.Some alleles are _________________, some are ________________. Dominant genes show their trait and ‘cover up’ recessive genes. IA (A) and IB (B) are dominant to i (O). D (+) is dominant to d (–)Some alleles are ___________________. This means both alleles fully express their trait.IA and IB are codominant with each other.What blood type will result from each genotype? IAiDDiiddIB IB DdIA IB ddIB iDdWhat are the possible genotypes for each blood type?A+AB-O-B+Punnett SquaresPunnett Squares are a tool for predicting the traits that will result from crossing certain genotypes.Monohybrid CrossesDihybrid Crosses1400175124460FOIL Method For Determining Mom’s Eggs and Dad’s Sperm00FOIL Method For Determining Mom’s Eggs and Dad’s SpermDNA Evidence Guided NotesName: __________________________DNA FunctionDNA encodes instructions for making all the ______________________of the bodyThese proteins determine our ___________________________107576747100Why is DNA so useful?________________________________________________________________________________________________________________________________________Is any other type of evidence as unique as DNA?What is the benefit of DNA compared to fingerprints?Types of DNA evidenceWhat kinds of evidence contain DNA that is suitable for forensic analysis?Most commonly used: _____________________ and _________________________Also useful: __________________ and _____________________What components of blood contain DNA?Why does saliva have DNA?What is ‘touch DNA’?DNA Structure3236259116056DNA stands for __________________________________.DNA is composed of two chains of ____________________ that are twisted around each other to form a double helix.020000DNA stands for __________________________________.DNA is composed of two chains of ____________________ that are twisted around each other to form a double helix.Chromosomes, Genes, and DNA – What’s the difference?3638549635Genes are ______________________ _______________________________ _______________________________Chromosomes are _______________ ______________________________ ______________________________ ______________________________During most of the cell’s life, the DNA is only loosely folded so it can be used to make proteins. But, before cell division, the DNA is tightly folded into the characteristic “X” shape of chromosomes.020000Genes are ______________________ _______________________________ _______________________________Chromosomes are _______________ ______________________________ ______________________________ ______________________________During most of the cell’s life, the DNA is only loosely folded so it can be used to make proteins. But, before cell division, the DNA is tightly folded into the characteristic “X” shape of chromosomes.DNA collection and HandlingWhat are the most common sources of DNA evidence?_______________________________________________________________________________________________________________________________________Investigators collect _____________ or __________________________________ for reference samples.DNA storageBlood and bodily fluids should be ______________________Tissue samples should be _________________________________________.DNA ExtractionBefore analysis, DNA must be extracted from cells._____________________ are used to dissolve the cell and nuclear membrane.______________________ are used to break down the proteins that are bound to DNA.______________________ is used to stabilize the DNA_______________________ is used to precipitate the DNADNA AmplificationOften investigators find very little DNA at a crime scene, so it must be ___________________________, before analysis.DNA is amplified using a process called _____________________________________________________PCR Stepsright59951___________________________________________________________________________The solution is cooled and ________________________ – short pieces of nucleotides that can begin the replication process -- are added.__________________________________, an enzyme that will attach individual nucleotides to the growing strands is added.Once the chain is complete, the process is repeated. The amount of DNA doubles each cycle. In three hours, one million copies can be made.020000___________________________________________________________________________The solution is cooled and ________________________ – short pieces of nucleotides that can begin the replication process -- are added.__________________________________, an enzyme that will attach individual nucleotides to the growing strands is added.Once the chain is complete, the process is repeated. The amount of DNA doubles each cycle. In three hours, one million copies can be made.-62193442259Gel electrophoresis is a method of separating molecules (usually proteins or DNA) by ____________________________________________________________.Samples are loaded into wells (indentations) of an gelAn electric current is put across the gel with the positive electrode on the opposite the wellsNegatively charged particles (such as DNA and some proteins) diffuse across the gel towards the positive electrode00Gel electrophoresis is a method of separating molecules (usually proteins or DNA) by ____________________________________________________________.Samples are loaded into wells (indentations) of an gelAn electric current is put across the gel with the positive electrode on the opposite the wellsNegatively charged particles (such as DNA and some proteins) diffuse across the gel towards the positive electrodeGel electrophoresis1143003304540Dyes are added to the samples so that you can see them as they move down the gelMolecules move down gel at different rates due to size and charge How?_____________________________ _______________________________Scientists will also run known samples for comparisonThis method is sufficient to separate DNA – additional methods often used for proteins4000020000Dyes are added to the samples so that you can see them as they move down the gelMolecules move down gel at different rates due to size and charge How?_____________________________ _______________________________Scientists will also run known samples for comparisonThis method is sufficient to separate DNA – additional methods often used for proteinsDyes are often added to the samples so that you can see them as they move down the gel4329654825500Molecules move down gel at different rates due to size and chargeWhat molecules move fastest? DNA fragments all have the same (negative) charge. So, DNA fragments separate purely based on size. Scientists will also run known samples for comparisonGel electrophoresis question 130670500A scientist added four substances to this gel.Small, highly positively charged chemicalsSmall, slightly positively charged chemicalsLarge, highly positively charged chemicalsLarge, slightly positively charged chemicalsWhich is which?4000020000A scientist added four substances to this gel.Small, highly positively charged chemicalsSmall, slightly positively charged chemicalsLarge, highly positively charged chemicalsLarge, slightly positively charged chemicalsWhich is which?3098800-139700The story … Police searched the home a person suspected of murder and found a shirt with blood stains. The blood type of the suspect, the victim, and the blood on the shirt was all O+, so the forensic serologist examined additional blood factors, including PGM.What PGM factor does each sample have?Who is the most likely source for the blood stain?What is the purpose of a reference sample? 020000The story … Police searched the home a person suspected of murder and found a shirt with blood stains. The blood type of the suspect, the victim, and the blood on the shirt was all O+, so the forensic serologist examined additional blood factors, including PGM.What PGM factor does each sample have?Who is the most likely source for the blood stain?What is the purpose of a reference sample? Gel electrophoresis Question 2Capillary Gel ElectrophoresisThe gels shown in the previous example are ____________ gels. Most of the time, forensic DNA analysis is done using a newer technique called _______________________________________________.Capillary gel electrophoresis is useful because it is better at __________________________________________ ______________________________________________ AND is _______________________________________.DNA fragments are ___________________________________________________ and are separated along a thin glass capillary tube (rather than an gel slab).A ____________________________ ‘reads’ the fluorescently marked fragments as they pass through the column, and showing ___________________________________ as each fragment size group goes through the detector, with _____________________________________________. _____________________________________________________ are also run through the column for comparison.STR Analysis Guided Notes Name:_____________________What is a gene?How much do genes vary between people?What do you think has more variation, coding DNA (genes) or non-coding DNA?Which would be of more use to forensic investigators? Coding or non-coding DNA?Introducing STRsSTR stands for ______________________________________________These are places (________) in DNA that contain a variable number of a short, repeated sequence of nucleotides. E.g. AGCAGCAGCAGCAGCAGCAGC (7 repeats)2981325635000or AGCAGCAGCAGCAGC (5 repeats)The number of repeats a person has is their ________ for that STR loci. Each person has two versions of every chromosome, so they have two alleles for each locus. (E.g. 6, 10 for a particular STR)Why STRs?STRs are ________________________! Small size means that the _____________________________________________, so only vary small amounts of DNA need to be recovered at the crime scene.Small size also means that the loci are more likely to ‘survive’ intact (______________________ ___________________ due to time or environmental conditions at the crime scene) STRs have been ____________________________________________. Investigators __________________________________________________ and can therefore correctly estimate the probability that a matching genotype could occur by chance.STRS are _______________________________________. There are a number of commercially available kits to amplify and separate STR alleles.Historical Side NoteThe first DNA analysis technique that was heavily utilized by forensic investigators were __________ (_________________________________________________________________________________). In RFLP analysis, restriction enzymes (enzymes that bind to specific sequences of DNA and cut it) were added to DNA. Since everyone’s sequence is different, the enzymes would cut DNA in different places, resulting in strands of DNA of different length. The DNA fragments would then be separated and compared using electrophoresis.The problem with RFLPS? They are ________________________________________. RFLP fragments can be up to 35,000 bp long, whereas STRS are always less than 450 bp.One of the most famous cases involving RFLPs was the Monica Lewinsky case. President Bill Clinton denied having sex with Monica Lewinsky, however, a semen stain on her dress was shown to match President Clinton’s DNA.left323215CODIS (_________________________________________________________) is a software program developed by the FBI that maintains local, state, and national databases of DNA profiles from convicted offenders, unsolved crime-scene evidence, and missing people.CODIS contains the genetic profiles of 13 different ‘core’ STR loci and 2 additional loci on the sex chromosomes.020000CODIS (_________________________________________________________) is a software program developed by the FBI that maintains local, state, and national databases of DNA profiles from convicted offenders, unsolved crime-scene evidence, and missing people.CODIS contains the genetic profiles of 13 different ‘core’ STR loci and 2 additional loci on the sex chromosomes.41592509461500CODIS441007526352500Interpreting STR Slab Gelsleft11430STRs can be ______________________________________ and then _____________________________________________________.In slab gel electrophoresis, the DNA is stained to form visible bands. Which end of the gel is at the negative electrode?What determines how far the fragments travel?020000STRs can be ______________________________________ and then _____________________________________________________.In slab gel electrophoresis, the DNA is stained to form visible bands. Which end of the gel is at the negative electrode?What determines how far the fragments travel?48903082157274429125-12636500left33020Multiple STRs can be run on the same slab gel if there is sufficient size difference between the alleles.How can you tell if a suspect is homozygous or heterozygous for a certain gene?If the common alleles for vWA are 14, 17, and 19, what is the genotype for suspect 1?Which suspect matches the crime scene DNA?00Multiple STRs can be run on the same slab gel if there is sufficient size difference between the alleles.How can you tell if a suspect is homozygous or heterozygous for a certain gene?If the common alleles for vWA are 14, 17, and 19, what is the genotype for suspect 1?Which suspect matches the crime scene DNA?2867025116840Identify the loci below!00Identify the loci below!4910571309534Interpreting Electropherogramsleft49530More commonly, STRs are analyzed via ______________________________________because it provides ______________________________ and is _______________________________. DNA is labeled, and every time fragments pass through a detector a peak is made. Smaller fragments pass through the detector first.Multiple STRs can be run in the same batch so long as the alleles are sufficiently different020000More commonly, STRs are analyzed via ______________________________________because it provides ______________________________ and is _______________________________. DNA is labeled, and every time fragments pass through a detector a peak is made. Smaller fragments pass through the detector first.Multiple STRs can be run in the same batch so long as the alleles are sufficiently different338645511684000left-25028100left354330Sometimes the data is presented in a table (yay!).The two alleles (number of repeated sections) for each locus is given. Homozygous alleles are listed twice for clarity. What do decimals (e.g. 9.3) mean?Which suspect matches the evidence? How could we calculate the probability that the suspect matched by chance?020000Sometimes the data is presented in a table (yay!).The two alleles (number of repeated sections) for each locus is given. Homozygous alleles are listed twice for clarity. What do decimals (e.g. 9.3) mean?Which suspect matches the evidence? How could we calculate the probability that the suspect matched by chance?4274820-6858000STR Analysis ExampleSTRs for Family RelationshipsSTRs (and DNA analyses) can also be analyzed to determine genetic relatedness. Why might genetic relatedness help police investigations?To identify ____________________ or ___________________________To determine ________________________________To solve _______________________________________________To find ____________________________________________________________________How can you tell if a person is the genetic parent of a child?406527013843000Can this be the father of the child?Why does the child have only one band at locus 3?Could the man still be the father if he didn’t have that allele at locus 3?38823907620Who is the baby daddy?How do you know?How can you exclude the others?How related are you to a full (non-identical) sibling?In general, multiply 0.5 by every step of separation in a relationship. Figure out the relatedness between … First cousinsAunt – nephewGrandparent – grandsonHalf siblings ................
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