Question

Discuss the characteristics of mammalian genomes that make them larger than prokaryotic genomes.

Short answer

The feature of mammalian genomes that makes them comparatively greater is the formation of multiple copies of transposable elements. Mammalian genomes include a high number of genes and some genes are repeated various times and present in multiple copies.

Step-by-step solution

Genome

A genome is a whole set of genetic instructions of an organism and consists of noncoding DNA, genes, and mitochondrial and chloroplast DNA.The genomes of mammals are larger and complex and consist of more than one DNA molecule and one or two sets of linear chromosomes.

Mammalian genome and prokaryotic genome

The eukaryotic genomes are larger than prokaryotic genomes as they vary in size and content. The amount of genes is higher in mammals and the amount of noncoding DNA is higher.

The well-characterized prokaryotic genome is comprised of circular, double-stranded DNA that has a single loop or circular chromosome. They are represented only once in their genome as they cannot be repeated several times and have smaller genome sizes.

Transposable elements

Most mammalian genomes comprise transposable elements. They comprise twenty to fifty percent of transposable elements and related sequences.

A transposable element is known as a jumping gene that is a DNA sequence and is responsible for altering its position inside a genome. They are the main elements of mammalian genome and are replicative transposons.

The mammalian genomes have both introns or noncoding regions and exons, making them larger than prokaryotic genomes as prokaryotes only possess exons.