Biology Webquest

DNA Fingerprinting

 

 

INTRODUCTION:

There was an assault and rape in the city this last spring.  Police crime scene investigators collected red stains and fingerprints from the crime scene as well as hairs and dried semen stains from the victim at the hospital.  This evidence was sent to the state crime lab and investigators used DNA fingerprinting to identify the rapist.  He has been accused and is now on trial.  You have been selected for the jury.

Many of the jurors do not understand the DNA evidence presented and have asked you to help explain what it all means because you have taken a biology class in which you studied DNA intensively.

 

THE TASK:

You will work in a team of four to collect and present information to the jury so that they understand the evidence against the accused.  For this you will need to summarize and explain background information on DNA and DNA fingerprinting technology; you will also need to explain why this is the preferred technology as well as some of the pitfalls of the technology.  In addition to presenting this information to the other jurors, you will also be prepared to answer any questions that they might have to help them evaluate the DNA evidence against the alleged rapist.

 

THE PROCESS:

In order to help your fellow jurors better understand the evidence, you and your teammates must:

·        Collect background information on DNA:  what it is, where it is found, why it is important, and why would investigators use DNA instead of other physical evidence.

·        Find out what DNA fingerprinting is and how it is done.  How is the DNA extracted, handled and examined? 

·        Find out what the techniques involved in DNA fingerprinting are and how they work. 

·        Find out what the problems or flaws with DNA fingerprinting are, and why it is important to address these.

Prepare and deliver a multimedia presentation to relate your findings to the jury.  Use illustrations, diagrams, graphs, animations, concept maps, etc. to help summarize what you have learned.  Your final slide(s) must list the group members, their roles, and documentation of all of your sources.  After your multimedia presentation, your group will act as a panel to answer any questions raised.

 

THE PRESENTATION:

In your multimedia presentation you should address the following:

·        Briefly summarize what DNA is and how it functions

·        Identify why DNA is the preferred evidence

·        Explain how it is possible to extract DNA from stains and fingerprints

·        How would the crime lab extract DNA from the samples collected

·        Explain how the crime lab would amplify DNA and why this might be important

·        Identify what it is the investigators are looking for and what is a DNA fingerprint

·        Explain how electrophoresis works

·        Explain what a Southern blot is and why it would be used

·        Explain the difference between RFLPs and VNTRs

·        Include all the correct terminology when referring to the enzymes and processes used

·        Identify the drawbacks of DNA evidence

·        Explain why the experts refer to “probability” when matching DNA

 

RESOURCES:

Background information on the basics of DNA

Your textbook:  Biggs et al (2000).  Biology The Dynamics of Life

http://www.dnaftb.org/dnaftb/15/concept/index.html

http://www.biology.washington.edu/fingerprint/dnaintro.html

Follow the links and do the DNA workshop activity to help understand the process in this site: http://www.pbs.org/wgbh/aso/tryit/dna/

http://www.bergen.org/AAST/Projects/Gel/Nucleic.htm

DNA Evidence and electrophoresis

http://www.firearmsid.com/KSP%20Evidence%20Manual/Biological%20Evidence.htm

http://www.bergen.org/AAST/Projects/Gel/index.html

http://www.pbs.org/wgbh/nova/sheppard/analyze.html

http://www.biology.washington.edu/fingerprint/dnaintro.html

http://www.dnalc.org/resources/dnadetective.html

http://www.dnalc.org/resources/BiologyAnimationLibrary.htm

 

DNA Technology: Southern blots/VNTRs/RFLPs

http://www.pbs.org/wgbh/nova/sheppard/analyze.html

http://www.dnalc.org/resources/dnadetective.html

http://www.dnalc.org/resources/BiologyAnimationLibrary.htm

 

Challenges or problems with DNA evidence

http://www.pbs.org/wgbh/nova/sheppard/analyze.html

http://www.accessexcellence.org/WN/NM/interview_dr_bruce_weir.html

http://members.ozemail.com.au/~dtebbutt/oj/ojsci2.html

 

Other resources that might help in various areas

http://howstuffworks.lycoszone.com/dna-evidence.htm

http://csdb.nidcr.nih.gov/csdb/chanchai_site/educ180/nih/DNA_tutorial.html

http://biology.about.com/cs/forensics/

http://www.karisable.com/crime.htm

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/RFLPs.html

 

Search engines

Alta vista  http://altavista.com/

Excite  http://excite.com/

Google  http://www.google.com

 

THE EVALUATION:

You will be evaluated on your presentation and the following panel session according to the following rubric:

 

Assessment Rubric

 

Exemplary
9-10

Good Effort
6-8

Marginal
3-5

Needs Work
1-2

Score

Adequacy of information

Summaries detailed; all information complete

Most of the information is adequate; few details missing

Missing information for key aspects of concepts

Inadequate information to explain concepts

 

Accuracy of information

All information is complete and accurate

Most information is accurate; few minor errors

Misconceptions present in few key concepts

Most information is sketchy or inaccurate

 

Graphics

Used variety of graphics to clearly state ideas

Used variety of graphics, mostly appropriate

Little variety or some inappropriate use of graphics

Few graphics; many not appropriate

 

Were all aspects addressed?

All aspects thoughtfully and clearly addressed

Most aspects addressed; some sketchy

Some aspects missing or not clearly addressed

Many aspects not addressed or sketchy

 

Oral presentation

Clearly spoken, well prepared, good grammar; good response to questions

Coherent, prepared; ok response to questions

Unprepared, questions not clearly addressed with misconceptions

Incoherent and failed to answer many questions

 

Cooperative work

Contributes to all aspects; takes responsibility for own segment; Values other viewpoints

Contributes to 3 of 4 aspects; does assigned segments; considers other views

Contributes to half of aspects; incomplete on assigned segment; tends to argue

Contributes little to group effort; assigned segment incomplete; usually argues, disregards other views

 

 

CONCLUSION:

Now that you have completed the DNA Fingerprinting Webquest, you should have a grasp of how forensic scientists use DNA technology.  What other ways can we use this technology?  Think about genetic diseases?  Missing children?  Medicine? And let’s not forget the social aspects:  should the government create and maintain a DNA Registry?  What are the implication of this registry?

 

 

Teacher Pages

This webquest was designed for a high school biology class to be used near the end of a unit in genetics.  Students should have some understanding of the molecular nature of DNA and the related technology before they embark on this quest.  With some modification, this may also be appropriate for advanced biology or advanced placement students.

Outcomes:

After this quest, students should

ü      Be familiar with the structure and function of DNA

ü      Understand the technology that has become prevalent in our society

ü      Understand that there are pitfalls in the technology, and know how to recognize some of them

ü      Know how to construct a multimedia presentation

ü      Be familiar with participating in a panel discussion

Timeline:

This quest should take about 2 weeks for the students to complete.  The amount of in-class time will depend on the availability of computers and internet access.

 

ALASKA STANDARDS ADDRESSED:

Science Content Standards.

A  Understand scientific facts, concepts, principles, and theories.

8a  Describe the nature of chemical reactions

10    Understand that living things are made up mostly of cells and that all life processes occur in cells

11    Understand that similar features are passed on by genes through reproduction

12    Distinguish the patterns of similarity and differences in the living world in order to understand the diversity of life and understand the theories that describe the importance of diversity for species

B  Possess and understand the skills of scientific inquiry.

3        Understand that scientific inquiry often involves different ways of thinking, curiosity, and the exploration of multiple paths.

C  Understand the nature and history of science.

1        Know how the words “fact,” “observation,” “concept,” “principle,” “law,” and “theory” are generally used in the scientific community

3        Understand that society, culture, history, and environment affect the development of scientific knowledge.

5        Understand that sharing scientific discoveries is important to influencing individuals and society and in advancing scientific knowledge.

7        Understand that major scientific breakthroughs may link large amounts of knowledge, build upon the contribution of many scientists, and cross different lines of study.

8        Understand that acceptance of a new idea depends upon supporting evidence and that new ideas that conflict with beliefs or common sense are often resisted.

D  Apply scientific knowledge and skills to make reasoned decisions about the use of science and scientific innovations.

1        Apply scientific knowledge and skills to understand issues and everyday events.

2        Understand that scientific innovations may affect our economy, safety, environment, health, and society and that these effects may be long or short term, positive or negative, and expected or unexpected.

3        Recommend solutions to everyday problems by applying scientific knowledge and skills.

4        Evaluate the scientific and social merits of solutions to everyday problems.

5        Participate in reasoned discussions of public policy related to scientific innovations and proposed technological solutions to problems.

6        Act upon reasoned decisions and evaluate the effectiveness of the action.

Mathematics Performance Standards

Statistics/Probability (Ages 15-18)

1        Analyze and draw inferences from a wide variety of data sources that summarize data; constructing graphical displays with and without technology

4        Analyze the validity of statistical conclusions and the use, misuse, and abuse of data caused by a wide variety of factors including choices of scale, inappropriate choices of measures of center, incorrect curve fitting, and inappropriate uses of controls or samples groups

5        Analyze data from multiple events and predict theoretical probability; find and compare experimental and theoretical probability for a simple situation, discussing possible differences between two results.

Reading Performance Standards

Ages 15-18

1        Apply knowledge of syntax, roots, and word origins, and use context clues and reference materials, to determine the meaning of new world and to comprehend text.

2        Summarize information or ideas from a text and make connections between summarized information or sets of ideas and related topics or information.

3        a.  Identify and assess the validity, accuracy, and adequacy of evidence that supports an author’s main ideas

4        Read and follow multi-step directions to complete complex tasks.

Writing Performance Standards

Ages 15-18

3        Use the conventions of standard English independently and consistently including grammar, sentence structure, paragraph structure, punctuation, spelling, and usage.

5        Cite sources of information using a standard method of documentation.