DNA FINGERPRINTING

ACHEAMPONG WIREDU

GENETICS BIO 2450 E158

04/14/19

 

                                                             DNA FINGERPRINTING

ABSTRACT

The objective of this laboratory experiment is to perform the techniques of molecular biology and used to manipulate the structure and function of molecules such as DNA and proteins in order to understand more about how they function. This technique of molecular biology is widely used for the purpose of identification of criminals from a set of possible suspects through what is called Forensic DNA fingerprinting.

INTRODUCTION

In this laboratory experiment, the conduction of a PCR based DNA fingerprinting was exercise on DNA from a stimulated crime scene and four different suspects. DNA fingerprinting is widely used approach to identify organisms and determine evolutionary relatedness and is used in forensics to identify criminals from a set of possible suspects. The residual traces of DNA are collected from a crime scene along with DNA sample from multiple suspects. Comparisons are made between both DNA’s and then matches in banding patterns created on the agarose gel between the crime scene sample and one of the suspects would implicate that particular suspect in the crime. The DNA molecule in all human cells is largely identical but scientists have identified regions in DNA where base pair difference are concentrated.

PROCEDURE

A set up of the restriction digests and have one tube labeled ENZ that contains the rehydrated restriction enzymes EcoRI and PstI. Restriction enzymes are then keep on ice during the preparation of restriction digests as enzymatic activity to decreases at higher temperatures. Colored tubes are labeled as follows: green = crime scene DNA, blue = suspect 1, orange = suspect 2, violet = suspect 3, pink = suspect 4, yellow = suspect 5 and clear = negative control. The enzymes and DNA samples were rehydrated and transferred to 10ul of the stock DNA into the corresponding colored tube and use water for negative control. 10ul of the enzyme is mix to each tube and sample mixture up and down a few times to homogenize the sample. Tube are place inside a dry bath and incubate for 45 mins at 37⁰C. After incubation period, store digests in the refrigerator. The agarose gel is prepared and samples are loaded in gel to quantify the results of restriction digests to determine if any of the suspect DNA sample match the DNA found at the crime scene. The suspect DNA banding pattern matching the pattern at the crime scene would implicate that individual in the crime.

RESULT

In this experiment, after the completion of the 9^th week, suspect was able to determined through the distance (bands) traveled on the gel. The yellow(suspect 5) colored was the suspect because of its traveled 15millimeters which matches the original crime scene results. The DNA of each individual is highly specific and the chances of two people having exactly the same DNA fingerprint is three million to 1 (except for identical twins).

CONCLUSION

In conclusion, DNA fingerprint can be use solving medical problems, crimes, biological evidence, diagnosis of inherited disorders and personal identification. For example solving medical problem, DNA fingerprint can be used to determine whether a particular person is the parent of the child. By comparing the DNA fingerprint of a mother and her child it is possible to identify DNA fragments in the child which are absent from the mother and must therefore have  been inherited from the biological father. In 2002, famous celebrity Elizabeth Hurley used DNA profiling to prove that Steve Bing was the father of her child.

 

REFERENCE:

1. Murphy, Erin (2017-10-13). “Forensic DNA Typing”. Annual Review of Criminology. 1: 497–515. doi:1146/annurev-criminol-032317-092127. ISSN 2572-4568.
2. “Test for determination of paternity”. ACTAGEN INC. 1984-02-28.