All questions of The Human Genome for Grade 9 Exam

Genetic Fingerprinting

Genetic fingerprinting or DNA fingerprinting is a technique used to identify individuals based on their unique DNA profiles. PCR and Restriction Fragment Length Polymorphism (RFLP) are two commonly used methods for genetic fingerprinting.

Polymerase Chain Reaction (PCR)

PCR is a powerful technique used to amplify a specific DNA sequence. It involves a series of repeated cycles of denaturation, annealing, and extension, resulting in the exponential amplification of a specific DNA fragment. PCR is used in genetic fingerprinting to amplify DNA from a sample, such as blood or tissue, and create multiple copies of a specific DNA fragment for analysis.

Restriction Fragment Length Polymorphism (RFLP)

RFLP is a technique used to identify variations in DNA sequences between individuals. It involves the use of restriction enzymes to cut DNA at specific sites, resulting in fragments of different sizes. The resulting fragments are separated by gel electrophoresis and visualized using a staining agent. The pattern of fragment sizes is unique to each individual and can be used to identify them.

Applications of Genetic Fingerprinting

Genetic fingerprinting has a wide range of applications, including:

- Forensic investigations: DNA evidence can be used to identify suspects or victims in criminal investigations.
- Paternity testing: DNA analysis can be used to determine biological relationships, such as paternity or maternity.
- Medical diagnosis: Genetic fingerprinting can be used to diagnose genetic diseases and identify carriers of genetic mutations.
- Evolutionary studies: Genetic fingerprinting can be used to study the evolutionary relationships between different species.

Conclusion

PCR and RFLP are two powerful techniques used in genetic fingerprinting. These techniques have revolutionized the field of forensic science and have a wide range of applications in medicine, biology, and genetics.

Most human cells have 2 of each of the 23 homologous monoploid chromosomes, for a total of 46 chromosomes. A human cell with an extra set out of the 23 normal ones would be considered euploid. Euploid karyotypes would consequentially be a multiple of the haploid number, which in humans is 23.

For DNA fingerprinting special single stranded DNA-probes are made in the laboratory. DNA-probes contain repeated sequences of bases complementary to those on VNTRs. These probes are made radioactive by labeling with radioactive isotopes. This step helps in detecting DNA fingerprints or variable number of tandem repeats (VNTRs). 

The basis of identification by DNA Profiling is the polymorphism. ... These highly variable sequences of DNA are known as VNTRs (Variable Number of Tandem Repeats) and STRs (Short Tandem Repeats) often referred to as Minisatellites and Microsatellites. These are noncoding regions and are repeated within genes.