Question

Long interspersed nuclear elements (LINEs) found in eukaryotic genomes

A) are mobile pieces of DNA called transposons that can copy themselves and move around the genome.
B) are thought to create genomic variability important to evolutionary adaptation.
C) are repeated 10-1000 times in clusters near centromeres and telomeres.
D) are part of constitutive heterochromatin.
E) are mobile pieces of DNA called transposons that can copy themselves and move around the genome, and they are thought to create genomic variability important to evolutionary adaptation.

Answer 1

Long interspersed nuclear elements (LINEs) found in eukaryotic genomes are transposons that copy themselves and move around within the genome. They contribute to genetic diversity and have roles in gene regulation, contributing to evolutionary adaptation. The human L1 element is a well-known example of a LINE that has significantly proliferated within the genome.

Step-by-step explanation:

Long interspersed nuclear elements (LINEs) found in eukaryotic genomes are repetitive DNA sequences that significantly contribute to the genomic diversity of an organism. These elements are a type of mobile DNA or transposons that can copy themselves and insert into new locations within the genome. Unlike simple cut-and-paste transposition, LINEs often copy themselves through a 'copy-and-paste' mechanism, facilitating their spread within the genome.

LINEs are important for several reasons. They can drive genetic diversity and evolution by creating mutations when they insert into new genomic locations. They also contribute to the regulation of gene expression and the reshaping of genomes over time. The ability of LINEs to promote genetic variation is thought to be critical to evolutionary adaptation, and although once deemed as 'junk DNA,' we now understand that LINEs have various functions and are subject to evolutionary selection.

The most well-known LINE in humans is the L1, which has significantly proliferated throughout the human genome and may impact its structure and function. L1 elements lack long terminal repeats (LTRs) and have their open reading frames (ORFs) flanked by untranslated regions (UTRs), distinguishing them from other transposons.