Module 5: Mendelian Genetics and Genetic Disorders

Before you begin the scientific investigation below, make sure to download the Fingerprint Inheritance Scientific Investigation Report. As you complete this scientific investigation, fill in any needed information on the report template. If you need more information about each section of the report, please visit the Developmental Module.

This scientific investigation is available below or in a printable version.

Introduction

Along with the rest of a person's features, fingerprints are formed while a fetus is developing. On the outer layer of the skin on the fingers, ridges form and grow into a pattern becoming a person's fingerprints. The fingerprint, which is unique to each individual, does not change as a person ages. Even though each fingerprint is unique, based on their pattern type, fingerprints can be grouped into three basic categories: loop, arch, and whorl. A description of each category is as follows:

• Loop: This type of pattern occurs in 60 – 70% of the population.  In a loop pattern, the ridges come in on one side, loop around in the middle of the pattern, and exit out the side that they entered.
• Whorl: This type of pattern occurs in about 25% of the population.  In a whorl pattern, the ridges occur in circles.
• Arch: This type of pattern occurs in about 5% of the population.  In an arch pattern, the ridges come in on one side and flow out on the other side.

Objectives

In this scientific investigation, you will:

• investigate the rate of occurrence of similar fingerprint patterns between siblings versus the rate of occurrence of similar fingerprint patterns between unrelated individuals.

Hypothesis

Using the Procedure and Data Collection section below, read through the procedural information for this scientific investigation. Based on your understanding of the procedure, develop your own hypothesis which describes your expected results. You should consider the following questions:  If siblings share 50% of their DNA, will they be more likely than unrelated people to have similar fingerprint categories? Record your hypotheses in the Hypothesis section of your Fingerprint Inheritance Scientific Investigation Report.

Procedure and Data Collection

1. Contact a variety of people to fingerprint. You should get permission to fingerprint the index fingers of a pair of people – both a sibling pair and a non-sibling pair. Make sure all of the individuals give you a fingerprint from the same hand.
2. Using the rubbing alcohol and cotton swabs, clean the index finger of each person.
3. Dry the index finger.
4. Roll the index finger on the black ink pad.
5. Roll the inked finger on the white paper.
6. Clean the ink off the finger.
7. Use the magnifying glass to examine the patterns of each fingerprint patterns.
8. Record your findings in the Data section of your Fingerprint Inheritance Scientific Investigation Report.
9. Repeat steps 1-8 with a minimum of 5 pairs of siblings and 5 non-sibling pairs. Make sure all of the individuals provide you with a fingerprint from the same hand.

Data

Use the tables provided in the Data section of your Fingerprint Inheritance Scientific Investigation Report to record your data from this scientific investigation. A sample data table for one pair is shown here.

Fingerprint Set 1

Name	Fingerprint and Description	Sibling Pair (Yes or No)	Category Match (Yes or No)

Data Analysis

In the Data Analysis section of your Fingerprint Inheritance Scientific Investigation Report, provide responses to the following questions. Make sure to completely answer each question.

1. What percentage of sibling pairs had similar fingerprint patterns?
2. Was the similarity of fingerprint patterns significantly higher or lower for sibling pairs versus unrelated pairs?
3. Did you have any identical twin pairs in your sample? If so, how did their fingerprints compare? If not, how do you think fingerprints of identical twins would compare?

Conclusion

Using the conclusion section of your Fingerprint Inheritance Scientific Investigation Report, compose three to four sentences describing an overall conclusion based on your data.  Was your hypothesis supported or not, and how do you know?  Use the data and notes that you collected from your experience to form you conclusion.  Make sure that you include information that you gained from data analysis to support your conclusion.

Experimental Sources of Error

On your Fingerprint Inheritance Scientific Investigation Report, provide responses to the following questions: Are there any sources of error? If so, what are they, and what could be done to minimize error?

Reflection

Once you have completed your scientific investigation, respond to the following questions in a brief 4-5 sentence paragraph response. In what way has genetics made you who you are? How are you unique? Are you similar to any other people? Does knowing your genetic make-up have any advantages or disadvantages?

Once you have completed your Fingerprint Inheritance Scientific Investigation Report and reflection, please submit your work to the dropbox.

 

Once you have completed this module, please complete the module test.