Pseudogenes are vitally important since they provide a record of how the genomic DNA has been changed without such evolutionary pressure and can be used as a model for determining the underlying rates of nucleotide substitution, insertion and deletion in the greater genome.

1. One member of a chromosome pair. 2. A gene similar in structure and evolutionary origin to a gene in another species.

Pseudogene transcripts can be processed into short interfering RNAs that regulate coding genes through the RNAi pathway. In another remarkable discovery, it has been shown that pseudogenes are capable of regulating tumor suppressors and oncogenes by acting as microRNA decoys.

Repetitive DNA: DNA sequences that are repeated in the genome. These sequences do not code for protein. One class termed highly repetitive DNA consists of short sequences, 5-100 nucleotides, repeated thousands of times in a single stretch and includes satellite DNA.

Generic repeated signals in the DNA are necessary to format expression of unique coding sequence files and to organise additional functions essential for genome replication and accurate transmission to progeny cells.

Based on these observations, we identified and integrated all the 100% identical repeats of at least 300 bp in the NCBI version 36.2 human genome reference assembly into non-overlapping regions, thus defining the Identical Repeated Backbone (IRB) of the reference human genome.

Repeated sequences (also known as repetitive elements, repeating units or repeats) are patterns of nucleic acids (DNA or RNA) that occur in multiple copies throughout the genome.

Hint: DNA and RNA are the nucleic acids present in the cells. RNA is mostly single-stranded while DNA is a double-stranded molecule….

Tandem repeat describes a pattern that helps determine an individual’s inherited traits. Tandem repeats can be very useful in determining parentage. Short tandem repeats are used for certain genealogical DNA tests. DNA is examined from microsatellites within the chromosomal DNA.

Direct repeats are a type of genetic sequence that consists of two or more repeats of a specific sequence. In other words, the direct repeats are nucleotide sequences present in multiple copies in the genome. Generally, a direct repeat occurs when a sequence is repeated with the same pattern downstream.

As with most transposons, LINE-1 migrations are generally harmless. In fact, LINE-1 has inserted itself around our genomes so many times over the course of human evolution that it alone makes up as much as 18% of our genome! LINE-1 insertions have been linked to different kinds of cancer, including colon cancer.

Transposase is an enzyme that binds to the end of a transposon and catalyses its movement to another part of the genome by a cut and paste mechanism or a replicative transposition mechanism.

Transposons themselves are of two types according to their mechanism, which can be either “copy and paste” (class I) or “cut and paste” (class II).

Since McClintock’s discovery, three basic types of transposons have been identified. These include class II transposons, miniature inverted-repeat transposable elements (MITEs, or class III transposons), and retrotransposons (class I transposons).

Transposons are segments of DNA that can move around to different positions in the genome of a single cell. These mobile segments of DNA are sometimes called “jumping genes” and there are two distinct types. Class II transposons consist of DNA that moves directly from place to place.

Genetic tests are used to diagnose certain disorders (for example, hemochromatosis and chromosome disorders such as Down syndrome and Turner syndrome). Genetics is also increasing the ability to predict what disorders a person is likely to develop.

Transposons are repetitive DNA sequences that have the capability to move (transpose) from one location to another in genome. Thus, they are considered an important contributor for gene and genome evolution (Kazazian, 2004). Transposons represent the most abundant repeats in most plant genomes.

Transposons: The Jumping Genes. Transposable elements (TEs), also known as “jumping genes,” are DNA sequences that move from one location on the genome to another.

In the case of bacteria, transposition mutagenesis is usually accomplished by way of a plasmid from which a transposon is extracted and inserted into the host chromosome. This usually requires a set of enzymes including transposase to be translated.

DNA transposons move using a cut-and-paste mechanism [6]. In contrast, retrotransposons move in a copy-and-paste fashion by duplicating the element into a new genomic location via an RNA intermediate [7].

Alu elements are responsible for regulation of tissue-specific genes. They are also involved in the transcription of nearby genes and can sometimes change the way a gene is expressed. Alu elements are retrotransposons and look like DNA copies made from RNA polymerase III-encoded RNAs.

An Alu element (or simply, “Alu”) is a transposable element, also known as a “jumping gene.” Transposable elements are rare sequences of DNA that can move (or transpose) themselves to new positions within the genome of a single cell. Alu elements are about 300 bases long and are found throughout the human genome.

Alu elements and protein translation. It has been known for a long time that Alu RNAs, transcribed from Alu elements, are present in the cytosol of primate cells. As mentioned previously, Alu elements contain the internal A and B boxes of the RNA polymerase III promoter from the 7SL RNA gene (Figure 1).

Alu PCR is a rapid and easy-to-perform “DNA fingerprinting” technique based on the simultaneous analysis of many genomic loci flanked by Alu repetitive elements, which allows the detection of genetic polymorphisms and mutations in human and primate genomes.