Question

Transposons and retrotransposons are two prominent classes of repetitive DNA in the nuclear genome of plants. Both of these repetitive DNA species are capable of moving throughout the plant nuclear genome via transposition. Describe the mechanism of transposition for each of these mobile DNA elements and further, which is considered one of the main contributors to increased nuclear genome size and which is more likely to influence gene expression post transposition. Explain your answer.

Answer 1

Transposon are jumping elements that jump from one location another. Transposon have the enzyme transposase through which the incision is made in the DNA at the site the cut is to made and site where it has to be inserted. The DNA ligase enzyme then seal the cut sequence. This type of transposon uses cut and paste type of mechanism, whether the DNA is cut from genome location and paste into other genome location.

Reterotransposon are the jumping elements which is a DNA sequence that first changed into RNA. Then this RNA is changed into DNA. This DNA is then incorporated into new genome. Reterotransposon uses copy and paste mechanism to copy the part of DNA sequence.

Retrotransposson are considered to increased the nuclear size as it uses the phenomenon of copy and paste mechanism to insert new DNA sequence.

Reterotransposon are considered to affect gene expression most because in this case DNA is changed into RNA and RNA is changed into DNA.