Question

Larger eukaryotes such as vertebrates contain much more noncoding DNA compared to smaller eukaryotes such as yeast. This means every time a vertebrate cell divides, it must spend more time and more energy replicating a large genome. What may this potentially high cost of having a bigger genome suggest about the selective pressures acting on organisms with smaller and larger genomes?

Answer 1

non-coding DNA sequences confer a key adaptive advantage associated with the ability to control a higher number of transcriptional programs

Step-by-step explanation:

A selective pressure can be defined as any type of external agent that affects an organism with certain genetic/phenotypic features, thereby exhibiting differential survival. Some examples of phenotypic selective pressure features include resistance to pollutants, diseases, illnesses, climate change, etc, while genetic selective features include, among others, a higher number of genes, higher non-coding DNA information, etc. Non-coding DNA sequences were originally thought to be selfish junk DNA without function. However, it has recently been shown that non-coding DNA sequences have critical regulatory roles, thereby it is expected that multicellular organisms with bigger genomes contain a higher amount of these sequences in order to modulate more transcriptional programs compared to organisms with smaller genomes, thereby being able to produce a higher number of cell types.