Answer: When the DNA collected on the crime scene is being analysed in the forensic lab, the results will be inconclusive, because error in DNA transcription, particularly in mRNA encoding leads to inheritable phenotype change by reprogramming the transcriptional network, without changing the DNA. Transcription errors are brief with no long-term consequences. Due to mRNA being short-lived and the erroneous proteins are degraded. A decrease in transcription accuracy triggers cellular identity change.
Explanation: This is called epimutation, a heritable modification that results in the change of gene expression, but not the DNA sequence. Epimutation is not associated with DNA mutation, but is associated with the loss or gain of DNA methylation or other heritable changes of the chromatin.
The beginning of the Cambrian Period is marked by the evolution of hard body parts such as calcium carbonate shells. ... These body parts fossilize more easily than soft tissues, and thus the fossil record becomes much more complete after their appearance.