We are so happy that you are joining us for the STEM Investigation Camp! Welcome to Day 2. We hope that you enjoyed Day 1 of the camp and are ready to have some cool new experiences with Science and gain some additional skills to help you solve the overarching mystery presented in the introduction for this camp!

DAY TWO BIG IDEA

A common reason for plane crashes is pilot error so we need to know who was at the controls. The pilot and co-pilot have DNA profiles on file (a necessary part of getting their license). There are blood stains on the dash and steering wheels on both sides of the cockpit. We collect those samples and extract DNA and type it. The students look at profiles I send as jpgs: The stains from the cockpit and the reference profiles from the pilot and co-pilot and see what matches what. We have another challenge however, identifying the bodies of the passengers who are a daughter and her father, and a female friend of the daughter who has a sister who lives in the area. Again we use DNA typing to identify the father and daughter (through kinship testing and knowing that a parent and child must share half of their DNA). The third victim is identified by default, but also the DNA profile can be compared against the surviving sister to see if they share markers in a way consistent with being siblings.

Day 2: Forensic Science

Forensics is the set of scientific tests or techniques used in connection with the detection of crime.

Jobs in Forensic Science: If you would like to know more about careers in forensics, here’s a link to information on what it takes to become a forensic scientist, as well as some of the jobs that they do:

Careers in Forensic Science

Top 13 Career Paths in Forensic Science

Meet Dr. Robert Allen, Professor of Forensic Sciences

Dr. Allen, Professor of Forensic Sciences at Oklahoma State University’s Center for Health Sciences in Tulsa, OK, also serves as Director of the OSU Human Identity Testing Laboratory. Dr. Allen, who is Board Certified by the American Board of Histocompatibility and Immunogenetics, has served as the Director of the H.A. Chapman Institute of Medical Genetics and as a Scientific Director of the American Red Cross.

The focus of his research is variability in human DNA and technologies for pathogen strain discrimination.

Dr. Robert Allen has created a DNA analysis challenge just for you! See below.

Today's Challenge: Forensic Science Experiments

Instructions for your forensic DNA analysis:

Look at the DNA profiles in the figures below. Each series of blue and green colored “peaks” in the figures represent the elements of the DNA profile that each of us has. If you look closely beneath each peak, you will see a box with some numbers. These boxes reveal the identities of the peaks, which are actually called alleles. An allele is a variety of a genetic marker. One genetic marker you may be familiar with are the blood groups, A, B, O, and AB. Your blood type is due to the collection of blood group alleles you possess. If you are type AB blood, you have one copy of an A allele and one copy of a B allele that together make you blood type AB. The alleles in the profiles are like the blood group alleles, only they are just differences that are revealed at the DNA level instead of in one’s blood type.

Count how many genetic markers are revealed in the DNA profiles shown. Above the peaks in the profile are the chromosomal addresses being typed (highlighted in green boxes). These “locus identifiers” reflect the chromosomal map coordinates where the genetic markers being typed are located. Any DNA typing lab in the world can read the locus identifiers and know exactly where the testing is focused. So to compare the DNA profiles, one looks at the allele identities (shown in the box beneath each peak and represented by a number on the first like (10, 11, 12, etc.) in the samples being compared and asks if the DNA profiles are identical or related in some way. In the case of this plane crash, two questions are being asked that DNA typing may answer:

1. Who was actually piloting the plane? Answering this question may be possible because there was a blood stain found in the wreckage on the steering wheel directly in front of the pilot’s seat in the cockpit. You need to compare that DNA profile with the profiles of the two pilots who were in the cockpit at the time of the crash. Those DNA profiles are available in the files of the airline because all flight staff are DNA profiled as part of their hiring. Take a sheet of paper and make three columns, one for the DNA profile from the blood stain and one each for the two pilots. Now compare the alleles for each DNA marker and see if any match.

2. The second question is a little more complex. The three passengers on this flight were a father, his daughter, and the daughter’s female friend. We recovered human remains from the wreckage but it was impossible to identify anyone just by looking, so we produced DNA profiles. If you notice the DNA results from the top-far left marker in the profile, you will see either the letter X or XY. This denotes the sex of individual from whom the sample was collected. Can the sex of the DNA profiles produced from the unidentified passengers provide any guidance as to who each of these victims might be? Also recall that the passenger manifest identified a man and his daughter as two of the three passengers on board. Try and use the laws of Mendelian genetics to see if any of the DNA profiles are consistent with being produced from a parent and child. For a parent:child comparison, half of the DNA in a child is inherited from a parent. Therefore, for every marker in the profiles, there should be at least one allele shared between the victim who could be a father and the victim who is his child. If we can do that, we can by default identify the third victim who would presumably be excluded as the daughter of the victim who is the father. Again, it is recommended that you get pencil and paper and write the alleles for each marker, for each sample in columns to facilitate making the comparisons.

Sample #1 from passenger compartment.

Sample #2 from passenger compartment.

Sample #3 from passenger compartment.

Who was piloting?

Meet Dr. James Creecy, Assistant Director of the Forensic Science Institute at UCO

James Creecy is the assistant director of the W. Roger Webb Forensic Science Institute and an assistant professor with the Department of Biology at the University of Central Oklahoma (UCO). He is a founding member of the UCO Center for Wildlife Forensic Science and Conservation Studies (C-FACS) and currently serves as the center’s co-director.

STEM@HOME Challenge

The STEM@HOME Challenges are hands-on STEM activities and challenges, designed to utilize materials many families may have at home or can easily source at the grocery store.

Fingerprinting

Use the materials below to take your fingerprints and examine them using your magnifying glass.

Materials Needed:

Pencil with eraser
(2) index cards or a sheet of paper
Scotch tape
Magnifying Glass - Don't have one at home? Try making one!

Fingerprinting Instructions:

Use the graphite pencil with eraser to make an “ink pad” on one of the index cards by coloring a large rectangle in the center of the card with the side of the pencil led until the rectangle is all colored in.
Press your fingertips on the “ink pad” being sure to get the whole surface of your fingertip coated in the graphite from the pencil.
Pull off a piece of scotch tape and press it on your thumb covering as much of the surface of your thumbprint as possible.
Pull the tape off of your thumb and stick it to the left side of the clean second index card.
Repeat steps 3 and 4 on your 4 remaining fingers going from your index finger down to your pinky finger.
Write your name at the top of the index card with your fingerprints.
What do you notice about the shapes on your fingerprints?

Reflection

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