DNA fingerprinting works because
A.
Most genes are dominant
B.
All organisms contain RNA
C.
The most important genes are differe
nt for every individual
D.
Different individuals have unique DNA sequences
C. The most important genes are different.
nt in every individual
D.
DNA sequences vary between individuals
The correct answer is D. DNA sequences vary between individuals.
DNA fingerprinting, also known as DNA profiling or genetic fingerprinting, works by analyzing specific regions of an individual's DNA to identify unique variations in the DNA sequence. These variations, known as genetic markers, are present in different locations throughout the genome.
To obtain a DNA fingerprint, several steps are followed:
1. DNA sample collection: DNA is extracted from a biological sample, such as blood, saliva, or hair.
2. Polymerase Chain Reaction (PCR): Specific DNA regions, known as short tandem repeats (STRs) or variable number tandem repeats (VNTRs), are amplified using PCR. These regions have repeating sequences that vary in length between individuals.
3. Fragment analysis: The amplified DNA regions are separated using a technique called gel electrophoresis. The DNA fragments are loaded into a gel matrix and subjected to an electric field, causing them to move through the gel. The fragments separate based on their size, allowing for comparison between individuals.
4. Visualization: The separated DNA fragments are visualized using techniques such as fluorescent dye staining or autoradiography. This creates a DNA fingerprint pattern, which consists of a series of bands representing the different allele lengths for each DNA region.
By comparing the DNA fingerprints of different individuals, scientists can determine if the same genetic markers are present or if there are differences in the DNA sequences. These differences can then be used to distinguish between individuals and establish their unique genetic profiles. Therefore, DNA fingerprinting works because DNA sequences vary between individuals.