What is tandem gene duplication?
Tandem exon duplication is defined as duplication of exons within the same gene to give rise to the subsequent exon. A complete exon analysis of all genes in Homo sapiens, Drosophila melanogaster, and Caenorhabditis elegans has shown 12,291 instances of tandem duplication in exons in human, fly, and worm.
What are the types of duplication?
Gene duplication can occur by several mechanisms, including whole-genome duplication (WGD) and single gene duplication. Single gene duplication includes four types, tandem (TD), proximal (PD), retrotransposed (RD), DNA-transposed (DD) and dispersed duplication (DSD) (Freeling, 2009; Hahn, 2009; Wang et al., 2012b).
What is reverse tandem duplication?
–Tandem duplications are adjacent to each other. –Reverse tandem duplications result in genes arranged in the opposite order of the original. –Tandem duplication at the. end of a chromosome is a. terminal tandem duplication.
What causes tandem duplications?
It is believed that tandem gene duplication could arise by unequal crossing over, which results from homologous recombination between paralogous sequences or nonhomologous recombination by replication-dependent chromosome breakages (Arguello et al. 2007).
What is tandem gene?
Tandemly arrayed genes reside within segments of DNA that are repeated head-to-tail a number of times. Clustered genes are linked but irregularly spaced, are often mutually inverted in an unpredictable pattern and are connected by non-conserved DNA.
What is meant by Diploidization?
Diploidization is the process of converting a polyploid genome back into a diploid one. Polyploidy is a product of whole genome duplication (WGD) and is followed by diploidization as a result of genome shock. It has also been hypothesized that vertebrate genomes have gone through two rounds of paleopolyploidy.
What is duplication and its types?
Gene duplications can arise as products of several types of errors in DNA replication and repair machinery as well as through fortuitous capture by selfish genetic elements. Common sources of gene duplications include ectopic recombination, retrotransposition event, aneuploidy, polyploidy, and replication slippage.
What are the two types of duplications?
If the duplicated sections are adjacent to the original, the process is known as tandem duplication, whereas if they are separated by nonduplicated regions, the duplication is said to be displaced.
What is Intrachromosomal duplication?
Intrachromosomal duplication is the duplication of genes within the same chromosome over the course of evolution (a-1). Alignment of DNA sequences exhibits homology between the two chromosomes (a-3). All segments were duplicated from the same ancestral DNA sequence as observed by the comparisons in b(i-iii).
How do gene duplications occur?
Gene duplication is the process by which a region of DNA coding for a gene is copied. Gene duplication can occur as the result of an error in recombination or through a retrotransposition event. Duplicate genes are often immune to the selective pressure under which genes normally exist.
What is the most common fate of a duplicated gene?
The most common fate for duplicate genes is the functional conservation of one paralog and non-functionalization of the other (Rensing, 2014) (Figure 4(a)).