Question

Some of the steps of DNA fingerprinting are given below. Identify the correct sequence from the options given.
A. Electrophoresis of DNA fragments
B. Hybridization with DNA probe
C. Digestion of DNA by RENs
D. Autoradiography
E. Blotting of DNA fragments to nitrocellulose membrane

a. C – A – E – B – D
b. A – C – E – D – B
c. C – A – B – E – D
d. A – E – C – B – D

Answer 1

DNA fingerprinting is the DNA analysis technique. DNA of different samples is extracted. Restriction enzymes are used for cutting DNA fragments. The separation of DNA is done by the electrophoresis process. Probes are used to hybridize DNA for analysis. Radiation is used to visualize and analyze the DNA fragments.

Complete answer:
DNA fingerprinting is the technique used to find relations between two people and living organisms. This is also known as DNA profiling, DNA testing, DNA analysis, Genetic profile, DNA identification, genetic fingerprinting and genetic analysis. Two types of DNA sequences are used for this technique : VNTR (variable number of tandem repeats) and STR (short tandem repeats).

Steps of DNA fingerprinting are as follows:
-The DNA is extracted from the cells: various samples containing genetic material must be treated with different chemicals.
-The DNA is cut into smaller fragments. It is done with the help of restriction enzymes. Endo-nucleases cut the DNA from specific sites.
-These are then run into electrophoretic units. With the help of electrophoresis, DNA fragments get separated on the basis of their charges and size. DNA fragments move to the positively charged electrode (anode). Smaller fragments move faster and then these fragments eluted from the gel.
-After the separation these DNA fragments are then blotted onto a nitrocellulose membrane.
-Probes(known sequence) are used to hybridize the DNA fragments.
-DNA fragments can only be visible under U.V radiation. These fragments are observed and analysed by performing autoradiography.

The correct sequence of DNA fingerprinting is C – A - E – B – D.

Hence, the correct answer is option (a).

Note: DNA is used for the analysis because in all bodily parts, tissues, and cells (except germ cells) our DNA is the same. Approximately 99 percent of our DNA is similar. Only 0.1 percent portion is used for DNA profiling. It is sufficient to make someone so unique. The repetitive and polymorphic properties of junk DNA are utilized to perform DNA fingerprinting.