Question

Interspersed repeated DNA

A) constitutes 25%-40% of most mammalian genomes.
B) is located in one region of most mammalian genomes.
C) is approximately 105-107 bp in length for each repeat.
D) can be classified into gene families, such as the Alu family.
E) constitutes 20%-40% of most mammalian genomes and can be classified into gene families, such as the Alu family.

Answer 1

Interspersed repeated DNA, including the Alu family, makes up 20%-40% of most mammalian genomes and has various functions beyond being mere 'junk DNA'.

Step-by-step explanation:

The question is about interspersed repeated DNA, which is a significant component of eukaryotic genomes including those of mammals. These repetitive sequences can constitute a significant portion of the genome and are dispersed throughout it rather than being located in a single region. Among these repetitive elements, the Alu family is a well-known example of short interspersed elements (SINEs) that are a type of retrotransposon present in large numbers throughout the human genome.

Answering the student's question, the correct option is E) which states that interspersed repeated DNA constitutes 20%-40% of most mammalian genomes and can be classified into gene families, such as the Alu family. Other types of repetitive DNA include satellite DNA and transposons, or transposable elements. It is now understood that these repetitive sequences have various functions, including gene expression regulation and genomic reshaping, which contribute to genetic diversity and evolution, debunking the idea that they are just 'junk DNA'.