Question

To resolve a parental dispute, the Honourable Judge ordered for DNA-fingerprinting of the child. The probable DNA finger prints of the child would be-

• A. 100% similar to the DNA prints of both the parents (father and mother)
• B. 100% similar to the DNA prints of the father.
• C. 100% similar to the DNA print of the mother
• D. About 50% of DNA prints would match either of the parents.

Hint:

In paternity or maternity disputes, trace the bands of the child. Any band in the child's DNA fingerprint that cannot be found in the mother's profile must be present in the biological father's profile.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
DNA fingerprinting, also known as DNA profiling or genetic testing, is a molecular technique utilized to identify genetic relationships by analyzing specific polymorphic regions of DNA.
In sexually reproducing diploid organisms, an offspring's genome is created by the fusion of maternal and paternal gametes.

Step 2: Detailed Explanation:
Each somatic cell of a child contains diploid chromosomal sets (\(2n\)), where one haploid set (\(n\)) is inherited from the biological mother and the other haploid set (\(n\)) is inherited from the biological father.
During DNA profiling, specific hypervariable regions such as Short Tandem Repeats (STRs) or Variable Number Tandem Repeats (VNTRs) are amplified and separated by gel electrophoresis to form a characteristic band pattern.
Because of this equal genomic contribution, every single band present in the DNA fingerprint of the child must find a corresponding match in either the mother's or the father's DNA fingerprint.
Specifically, about 50% of the bands in the child's profile are inherited from the biological mother, and the other 50% are inherited from the biological father.
A child's DNA profile cannot be 100% identical to either of the parents individually, as that would only occur in clonal or asexual reproduction.
Likewise, it cannot be 100% similar to both parents simultaneously because the parents themselves possess different genetic makeups.

Step 3: Final Answer:
Hence, the probable DNA fingerprints of the child will show about 50% similarity to each of the parents.