Question

Which statement is TRUE?

Hint: When discussing the association of transposition with genome replication, I said that it happens mainly in eukaryotes. This association occurs in both bacteria and eukaryotes, where transposition happens when donor DNA is still hemimethylated (shortly after replication). The Transposon moves to a nearby location, which has not yet undergone replication.
a) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is fully methylated (state of DNA prior to replication).
b) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is single-stranded.
c) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is present in heterochromatin.
d) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is hemimethylated (state of DNA after replication).

Answer 1

The true statement is (d) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is hemimethylated (state of DNA after replication).

Step-by-step explanation:

Transposition is a process in which DNA elements, called transposons or jumping genes, move from one location to another in the genome. In both bacteria and eukaryotes, transposition occurs when the donor DNA is still hemimethylated, meaning it has undergone replication but one strand is methylated and the other is not. At this stage, the transposon can move to a nearby location that has not yet undergone replication.

For example, in bacteria, the transposition of Tn10 occurs when the donor DNA is hemimethylated. Similarly, in maize, the transposition of Ac/Ds elements also occurs when the donor DNA is in a hemimethylated state. This allows the transposons to move to nearby locations and contribute to genetic diversity.

In conclusion, the correct statement is (d) The transposition of Tn10 (bacteria), as well as Ac/Ds elements (maize) occurs if the donor DNA is hemimethylated (state of DNA after replication).