Question

Mobile genetic elements such as viruses and transposons continue to exist despite the fact that their activity would seem to disrupt the fidelity of hereditary material. This is because:

1) Their mechanisms are too advanced for the cells defenses to control
2) Their activity is so infrequent that there is no real effect on the DNA
3) The occasional DNA re-arrangements and additions are beneficial to the long term
4) Their continued existence is in fact still a scientific mystery that is not seen to make sense

Answer 1

Transposons such as viruses and transposable elements continue to exist because their activity can be beneficial in the long term by causing occasional DNA rearrangements and additions (option 3).

Step-by-step explanation:

Transposons, such as viruses and transposable elements, continue to exist despite the potential disruption of hereditary material for several reasons. Firstly, most transposition occurs in the non-coding regions of the genome, which do not code for proteins.

Additionally, eukaryotic organisms have duplicate copies of each gene, so if one copy is inactivated, the other can compensate. Moreover, mechanisms exist to silence transposons after their transposition, reducing the risk of genetic damage. Finally, there is evidence that small interfering RNAs (siRNAs) can target and destroy transposon transcripts.

Overall, the occasional rearrangements and additions caused by transposons can be beneficial in the long term, leading to genetic diversity and the selection of new genotypes and phenotypic characteristics. Therefore, the correct option is 3) The occasional DNA rearrangements and additions are beneficial to the long term.