Question

2. Eukaryotes have more noncoding DNA per gene than prokaryotes, as well as more variable amounts of noncoding DNA per gene (than prokaryotes). How could this be explained by differences in effective population size? Or alternatively, how could this be explained by differences in physical cell size (cellular volumes)? Or in either case, what might be the role(s) of transposable elements?

Answer 1

In case of the eukaryotes the gene has more variable amount of non-coding DNA as compared to the prokaryotes and one of the most prominent reasons is the physical cell size. The cell size of the prokaryotes which are single celled do not have a mechanism that develops a lot of variable non-coding regions. However due to the large cell size in the eukaryotes, the transcription process develops junk and non-coding regions on the eukaryotes. This might also have a lot to do with the presence of transposable elements on the DNA sequence which changes its position in a genome and might create or reverse mutations. It might also lead to altering cell’s genetic identity and genome size. The elements play a very important role in the overall developmental process. In eukaryotes, there is a high tendency for the transposon to insert in the functioning gene. The insertion of the transposon into the exons, introns or even into the DNA flanking the genes might lead to the destruction of the gene activity. Due to the transposon, the eukaryotes might have non-coding regions