Project Description
This project was focused on learning new biology skills through the investigation of a mock murder. We learned about what forensic scientists do and how they use biology to help them solve crimes. Some of the things we did were DNA fingerprinting, karyotypes, and blood type analysis. These all related to topics that we were learning in class. Looking at karyotypes helped us understand chromosomes and chromosomal disorders. DNA fingerprinting was a good way to learn that everyone's DNA is different, and can be used to identify them much like a fingerprint.
The murder that we were investigating was that of Carlton Comet. He was on a picnic with Sam Sophomore, Nancy Normal, Fred Flimmer, Glen Glee, and Theresa Terra. It suddenly darkened, and when the light returned Comet was dead. We had to learn new forensic skills and use them to decipher clues and figure out who was the murderer. We then had to put together a case and present it to a jury. My group was granted a warrant for arrest.
The murder that we were investigating was that of Carlton Comet. He was on a picnic with Sam Sophomore, Nancy Normal, Fred Flimmer, Glen Glee, and Theresa Terra. It suddenly darkened, and when the light returned Comet was dead. We had to learn new forensic skills and use them to decipher clues and figure out who was the murderer. We then had to put together a case and present it to a jury. My group was granted a warrant for arrest.
Our Case
Content
DNA Fingerprinting- DNA fingerprinting is a technique that is used by forensic scientists to study the unique patterns in someones DNA in order to identify a suspect. This DNA can be taken from hair, blood, or even tissue samples. DNA fingerprinting is done using gel electrophoresis and analyzing and comparing the color bands. We used DNA fingerprinting as a way of proving that Nancy Normal had killed Carlton Comet, as her DNA fingerprint matched the one taken from the crime scene.
Ink Chromatography- Ink chromatography is a way of separating the different colors of ink that make up a pen. Every pen is composed of a unique mixture of inks, even if the pens are the same color. This is used to analyze the ink of notes that were left at a crime scene and compare it to the ink of a suspects pen. We performed ink chromatography to determine who's pen matched the note that was left at the crime scene, which is a common technique in forensics.
Karyotypes- Karyotypes are a profile that show all of a person's chromosomes. They are used to determine whether or not someone has a chromosomal disorder. In our case, many people has chromosomal disorders. Nancy Normal, the murderer, had Triple X Syndrome, which means that she had an extra x chromosome. This is useful in our case because it is a potential motive, and we were able to easily identify it using her karyotype.
Pedigree- A pedigree is a chart that shows not only all of a persons relatives, but also any genetic disorders they might have. This way the disorder can be tracked down through the family line and scientists can learn more about how it is inherited and predict who it might affect. We created a pedigree to sort out all of the relatives in our case, as well as track the frequent cases of genetic disorders. Nancy Normal suffered from a genetic disorder, Huntington's Disease, which she inherited from her father. This was an important potential motive because Huntington's can affect your judgment.
DNA Structure- DNA is shaped as a double helix consisting of nucleotides and a sugar phosphate backbone. The sugar phosphate backbone provides stability, while the nucleotides determine what trait or protein the DNA codes for. There are four different types of nucleotides, Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). Only A and T can fit together, and only C and G can fit together. DNA structure was an important part of this unit, as everything that we did was related to DNA.
DNA Replication- DNA replication is vital for all lifeforms. In order for our bodies to make new cells, we must first duplicate the DNA.
1. The DNA molecule is unzipped by the enzyme Helicase
2. RNA Primase adds primers for the DNA Polymerase to start at and attach to
3. On the leading strand (5' to 3') the Polymerase simply goes along the strand and fills in the correct nucleotide sequence
4. On the lagging strand (3' to 5') the Primase must add fragments of primers all along the strand for the Polymerase to attach to and fill in nucleotides. This strand is more complicated for replication because Polymerase can only go 5' to 3'.
5. Ligase connects all of the Okasaki fragments on the lagging strand
DNA is considered to be semi-conserved because it keeps one strand of the parent DNA and adds one new strand.
Dominant Genes- Dominant genes are ones that will always be expressed if they are present. If you inherit a dominant gene you will have that trait. They are usually represented with a capital letter.
Recessive Genes- Recessive genes are ones that won't always be expressed when they are present. If you inherit one recessive gene and one dominant gene, the recessive one won't be expressed. If you inherit two recessive genes then they will be expressed. They are usually represented with a lower case letter.
Alleles- Alleles are the different variations of a gene, usually caused by genetic mutations. You usually have two alleles for each trait, one inherited from your father and one from your mother. These alleles can be either dominant or recessive. Dominant genes are ones that will always be expressed if they are present. If you inherit a dominant gene you will have that trait. They are usually represented with a capital letter.
Recessive genes are ones that won't always be expressed when they are present. If you inherit one recessive gene and one dominant gene, the recessive one won't be expressed. If you inherit two recessive genes then they will be expressed. They are usually represented with a lower case letter. This relates to our project because we studied certain inherited disorders that can be either dominant or recessive alleles.
DNA Mutations- DNA mutations are when the DNA of an organisms changes. Mutations can sometimes be positive, sometimes negative, and sometimes have no effect. Mutations can be caused by DNA not copying correctly, or being damaged. Mutations can be passed on to offspring, so they are inherited. In our project there were some diseases like Huntington's Disease that could be due to DNA mutations.
Chromosomal Disorders- Chromosomal disorders are caused by too many chromosomes, too few, or structural abnormalities. There are many different chromosome disorders that have a wide range of symptoms. Some of the disorders seen in our project were Triple X Synrome, XYY Syndrome, and Trisomy 21. Chromosomal disorders can be discovered through karyotypes, a way of creating a profile to study all of a person's DNA.
Ink Chromatography- Ink chromatography is a way of separating the different colors of ink that make up a pen. Every pen is composed of a unique mixture of inks, even if the pens are the same color. This is used to analyze the ink of notes that were left at a crime scene and compare it to the ink of a suspects pen. We performed ink chromatography to determine who's pen matched the note that was left at the crime scene, which is a common technique in forensics.
Karyotypes- Karyotypes are a profile that show all of a person's chromosomes. They are used to determine whether or not someone has a chromosomal disorder. In our case, many people has chromosomal disorders. Nancy Normal, the murderer, had Triple X Syndrome, which means that she had an extra x chromosome. This is useful in our case because it is a potential motive, and we were able to easily identify it using her karyotype.
Pedigree- A pedigree is a chart that shows not only all of a persons relatives, but also any genetic disorders they might have. This way the disorder can be tracked down through the family line and scientists can learn more about how it is inherited and predict who it might affect. We created a pedigree to sort out all of the relatives in our case, as well as track the frequent cases of genetic disorders. Nancy Normal suffered from a genetic disorder, Huntington's Disease, which she inherited from her father. This was an important potential motive because Huntington's can affect your judgment.
DNA Structure- DNA is shaped as a double helix consisting of nucleotides and a sugar phosphate backbone. The sugar phosphate backbone provides stability, while the nucleotides determine what trait or protein the DNA codes for. There are four different types of nucleotides, Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). Only A and T can fit together, and only C and G can fit together. DNA structure was an important part of this unit, as everything that we did was related to DNA.
DNA Replication- DNA replication is vital for all lifeforms. In order for our bodies to make new cells, we must first duplicate the DNA.
1. The DNA molecule is unzipped by the enzyme Helicase
2. RNA Primase adds primers for the DNA Polymerase to start at and attach to
3. On the leading strand (5' to 3') the Polymerase simply goes along the strand and fills in the correct nucleotide sequence
4. On the lagging strand (3' to 5') the Primase must add fragments of primers all along the strand for the Polymerase to attach to and fill in nucleotides. This strand is more complicated for replication because Polymerase can only go 5' to 3'.
5. Ligase connects all of the Okasaki fragments on the lagging strand
DNA is considered to be semi-conserved because it keeps one strand of the parent DNA and adds one new strand.
Dominant Genes- Dominant genes are ones that will always be expressed if they are present. If you inherit a dominant gene you will have that trait. They are usually represented with a capital letter.
Recessive Genes- Recessive genes are ones that won't always be expressed when they are present. If you inherit one recessive gene and one dominant gene, the recessive one won't be expressed. If you inherit two recessive genes then they will be expressed. They are usually represented with a lower case letter.
Alleles- Alleles are the different variations of a gene, usually caused by genetic mutations. You usually have two alleles for each trait, one inherited from your father and one from your mother. These alleles can be either dominant or recessive. Dominant genes are ones that will always be expressed if they are present. If you inherit a dominant gene you will have that trait. They are usually represented with a capital letter.
Recessive genes are ones that won't always be expressed when they are present. If you inherit one recessive gene and one dominant gene, the recessive one won't be expressed. If you inherit two recessive genes then they will be expressed. They are usually represented with a lower case letter. This relates to our project because we studied certain inherited disorders that can be either dominant or recessive alleles.
DNA Mutations- DNA mutations are when the DNA of an organisms changes. Mutations can sometimes be positive, sometimes negative, and sometimes have no effect. Mutations can be caused by DNA not copying correctly, or being damaged. Mutations can be passed on to offspring, so they are inherited. In our project there were some diseases like Huntington's Disease that could be due to DNA mutations.
Chromosomal Disorders- Chromosomal disorders are caused by too many chromosomes, too few, or structural abnormalities. There are many different chromosome disorders that have a wide range of symptoms. Some of the disorders seen in our project were Triple X Synrome, XYY Syndrome, and Trisomy 21. Chromosomal disorders can be discovered through karyotypes, a way of creating a profile to study all of a person's DNA.
Reflection
One downside of this project was that some members were more involved than others. A few people weren't as active as delegating themselves tasks to do and ways to help our group. It was difficult to avoid a natural division between members, as is common in groups of diverse people.
The corresponding upside of this was that the other members were able to involve those people in the group and help them find ways to participate and support our group. We were able to use good communication skills to get everyone involved with working on the presentation. During the hands-on parts of the lab everyone was enthusiastic to participate.
Another downside is that our group ended with no time to practice our presentation and prepare our best case for the judges. We made sure to spend time revising and perfecting our slides, but forgot to leave an extra 20 minutes or so at the end for presentation practice. This could be rectified by improving our time management skills and organization.
The final upside of this project was that everyone in our group got along well. There was minimal arguing, and what arguments there did occur were usually structured and academic in nature. We were able to easily reach a solution to all of our problems that we faced, and every member was willing to do their part to ensure the duration of the project went smoothly.
The corresponding upside of this was that the other members were able to involve those people in the group and help them find ways to participate and support our group. We were able to use good communication skills to get everyone involved with working on the presentation. During the hands-on parts of the lab everyone was enthusiastic to participate.
Another downside is that our group ended with no time to practice our presentation and prepare our best case for the judges. We made sure to spend time revising and perfecting our slides, but forgot to leave an extra 20 minutes or so at the end for presentation practice. This could be rectified by improving our time management skills and organization.
The final upside of this project was that everyone in our group got along well. There was minimal arguing, and what arguments there did occur were usually structured and academic in nature. We were able to easily reach a solution to all of our problems that we faced, and every member was willing to do their part to ensure the duration of the project went smoothly.