A mutation named with the blend of insertion and deletion. It refers to
a length difference between two ALLELES where it is unknowable if the difference was originally caused by a SEQUENCE
INSERTION or by a SEQUENCE DELETION.
What is an indel in genomics?
Sehn, in Clinical Genomics, 2015. Insertion–deletion mutations (indels) refer
to insertion and/or deletion of nucleotides into genomic DNA and include events less than 1 kb in length
.
What does indel mutation mean?
A mutation named with the blend of insertion and deletion. It refers to
a length difference between two ALLELES where it is unknowable if the difference was originally caused by a SEQUENCE
INSERTION or by a SEQUENCE DELETION.
Where do indel mutations occur?
Indels occur almost exclusively in
repeat regions composed of homopolymers and multimeric simple sequence repeats
, demonstrating the importance of sequence context for indel mutations. Despite purifying selection, some indels occur in protein-coding genes.
What causes indel?
Mechanisms for small indel events are
replication slippage
(as seen in STR regions), recombination, unequal crossing over, and tandem duplication caused by imperfect repair of double strand breaks. Larger indels may be caused by segmental duplications and transposable elements.
What occurs in a deletion mutation?
A deletion mutation occurs when
a wrinkle forms on the DNA template strand and subsequently causes a nucleotide to be omitted from the replicated strand
(Figure 3). Figure 3: In a deletion mutation, a wrinkle forms on the DNA template strand, which causes a nucleotide to be omitted from the replicated strand.
What causes transversion mutation?
Transversion, in molecular biology, refers to a point mutation in DNA in which a single (two ring) purine (A or G) is changed for a (one ring) pyrimidine (T or C), or vice versa. A transversion can be spontaneous, or it can be caused by
ionizing radiation or alkylating agents
.
How can you tell an indel?
Indels are the most common structural variant that contribute to pathogenesis of disease [2], gene expression and functionality. Current approaches to identify indels include
de-novo assembly of unaligned reads [3]
, read splitting [4,5], depth of coverage analysis [6] and analysis of insert size inconsistencies.
What is insertion or deletion?
Insertion. An insertion changes the DNA sequence by adding one or more nucleotides to the gene. As a result, the protein made from the gene may not function properly. Deletion. A
deletion changes
the DNA sequence by removing at least one nucleotide in a gene.
How do mutations occur?
Mutation. A mutation is a change in a DNA sequence. Mutations can result from
DNA copying mistakes made during cell division
, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.
What does a point mutation do?
Point mutations are a large category of mutations that describe
a change in single nucleotide of DNA
, such that that nucleotide is switched for another nucleotide, or that nucleotide is deleted, or a single nucleotide is inserted into the DNA that causes that DNA to be different from the normal or wild type gene …
What is a silent mutation and what does it do?
A silent mutation is
a form of mutation that does not cause a significant change in the amino acid
. As a result, the protein is still functional. Because of this, the changes are regarded as though they are evolutionarily neutral.
Are indels random?
Asymmetric somatic hybridization induces genetic variation in a non-random manner. SNPs and small indels are two major natural genetic variation in organisms [41], so their rates determine the extent of genetic variation, and therefore, the strength of selection pressure.
How does deletion affect protein structure?
Therefore, the residue removed in loops will dictate the structural rearrangements that occur rather than a general “whole loop” effect being observed. … This stands to reason given that deletions like substitutions, of an amino acid buried in the core of a protein can be
disruptive
to protein structure and function.
Are indels bad?
Like SNPs and structural variation, INDELs are of great interest because they can alter human traits and
can cause human diseases
.
Are deletions more common than insertions?
Deletions are
about twice as frequent as insertions
for nuclear DNA, and in mitochondrial DNA, deletions occur at a slightly higher frequency than insertions [10]. Deletion events are also found more common than insertions in both mouse and rat [11-13].
