CramX Logo
Exploring DNA Profiling - Document preview page 1

Exploring DNA Profiling - Page 1

Document preview content for Exploring DNA Profiling

Exploring DNA Profiling

Learn how DNA profiling helps identify individuals through unique genetic patterns. This student activity explores real-world applications like forensics and genealogy using simulations and key concepts like STRs and gel electrophoresis.

Daniel Miller
Contributor
0.0
0
12 months ago
Preview (3 of 9 Pages)
100%
Log in to unlock
Page 1 of 3
Exploring DNA Profiling - Page 1 preview imageStudent Exploration: DNA ProfilingDirections: Follow the instructions t o g o through the simulation. Respond to the questions andprompts in the orange boxes.Vocabulary:DNA polymerase, DNA profiling, gel electrophoresis, gene, mutation, non-coding region,polymerase chain reaction, primer, short tandem repeatPrior Knowledge Questions(Do these BEFORE using the Gizmo.)In 1985, Darryl Hunt was convicted of murder. While Hunt was in jail, a new method for analyzing DNAevidence was invented. The DNA evidence on the victim did not match Hunt's DNA but did match that ofanother prisoner. After 19 years spent behind bars. Hunt was finally declared innocent and released fromprison in 2004.1.DNA is used to tell people apart. What aspects ofDNA do you think make this possible?2.What are some possible uses for technology thatidentify people based on their DNA?The different arrangements/sequences of basepairs help create differences in our DNAcanDNA fingerprinting can be used to identifysuspects and link them to crime scenes, or theDNA found in our saliva can be used ingenealogy and help determine ethnic origins.GizmoWarm-upDNA profiling does not just compare people's entire genome side by side.Instead, a very particular part of the DNA is compared. In the DNAProfilingGizmo you will leam about the differences in DNA that make DNA profilingpossible and you will use that knowledge to design your own DNA profilingtest.Clickonthe crime lab in theForensic trainingsection You are looking atastrand ofDNA. DNAcontainsgenesandnon-coding regionsbetween genes Click onNon-coding A.1.You are looking at a portion of the non-coding Asection for three different people. Are these sectionsthe same or different? ExplainThese sections are different as some sectionsare different in length and have different basepair sequences.Person 1 and 3 have identical sequences intheir gene, whereas person 2 has a differentnucleotide sequence.2.Click Previous then click on Gene A. Are theredifferences in gene A for the three people?
Page 2 of 3
Exploring DNA Profiling - Page 2 preview imageActivity A:Getthe Gizmo ready:Forensic trainingClick on Forensic training and Start againIntroduction: In this activity, you will learn about the principles and techniques that make DNA profilingpossible. Genes code for specific traits. In people, the DNA sequences for most genes are nearly identical,since any change could result in a harmful disorder. The areas between genes do not code for any essentialtraits, so a change to the DNA sequence doesn't have any major consequences. As a result, these regionstend to be very different for different people.Question: How can the differences in DNA be exploited to perform DNA profiling?1.Observe:Clickonnon-coding A.What do you see in the middleofeach of the threeDNAsequences?In the middle of each of the three DNA sequences, I see a repeated sequence ofTAAA(Top) and A l l i (bottom)2.Compare: Turn onShow short tandem repeats (STRs).An STR isashort, repeated sequence ofDNA,likeTAAA.Theycan be repeatedanynumber of times without affecting the traits of the person. Differentpeople usually have different numbers of repeats.What does this do to the length of each person's non-coding regions?A DNA sequence's number of STRs refers to the number of times a certain short sequenceof nucleotides is repeated in a given area of the DNA, adding variation in those sections'lengths across people.3.Create:Your goalis to make copies of the STR region. To do this,youwill makeprimersthat surround theSTR region. A primer is a short sequence of DNA that acts as a starting point for DNA replication.Click Next. Click on person 1's DNA to separate the two strands. Drag along the AAGGC nucleotides, andthen the TCGCC nucleotides to create primers. Click Next. The Gizmo will add the same primers to the twoother people.What doyounotice about where theprimersattach in each person?Inoticed that the primers attach to the same parts of the DNA strand; the beginning andends.4.Observe:Click Next.Anenzyme called DNA polymeraseusestheprimers asastarting point tocopytheDNA. CopyingDNAusingprimers is a techniquecalledPolymerase chain reaction (PCR)
Page 3 of 3
Exploring DNA Profiling - Page 3 preview imageClick Next again. The DNA segments are copied millions of times.What do you notice aboutlhelengths of the copied DNAsirands?I noticed that the lengths of lhe copied DNA strands are different for each individual5.Compare: Click NextGel electrophoresis is used Io separate DNA strands of different lengths. Anelectric current is passed through the gel. As the current moves from top to bottom, il pulls lhe DNA andloading dye along wilh it. Click on the power box Io turn il on.A.Which person's DNA band traveled the farthest?Person 2Shortesl?Person 1B.Turnon Show labels What do you notice about the length ofThe longer the strand, the shorterthe DNA versus the distance it traveled down lhe gel?it will travel. Additionally, lheshorter the DNA strand, lhelonger it will travel.C.Can you identify people by comparing the length of STR regions on a gel? ExplainYes. you're able to identify people by comparing the length of STR regions on a gel as lhelength of STR regions differ from person to person. Because of this separation, lhe gel acquiresa distinctive pattern of bands that corresponds to the sizes of the various STR fragments in lhesample. If a sample matches any of the known people, it may be determined by comparing thepattern of bands on the gel from the sample to those patterns.6.Observe: ClickNext.Then select GeneA.A.Does gene A have any STRs?Gene A does not have any STRsBecause genes are segments of DNA that holdlheinstructions for producing proteins theyusually don't have large variable regions like STRs.B.Are there any differences in gene A between the individuals?Person 1 and 3 have identicalsequences, whereas person 2has different ones.Genes may contain smallmutationsthat don't affect the length of the segment.Create primers and copy the DNA. What do you notice aboutthe length of the duplicated regions?They re all the same length.
Preview Mode

This document has 9 pages. Sign in to access the full document!