What is a duplication in biology?
Duplication is a type of mutation that involves the production of one or more copies of a gene or region of a chromosome. Gene and chromosome duplications occur in all organisms, though they are especially prominent among plants. Gene duplication is an important mechanism by which evolution occurs.
What is an example of duplication in biology?
If a deletion is a missing ingredient in the recipe, a duplication is an extra ingredient. One example of a rare genetic disorder of duplication is called Pallister Killian syndrome, where part of the #12 chromosome is duplicated.
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 it called when chromosome duplication?
Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene.
What is tandem duplication in biology?
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 is displaced duplication?
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. Duplications may affect phenotype by altering gene dosage.
What is Trisomy 21 also known as?
‘ Down syndrome is also referred to as Trisomy 21. This extra copy changes how the baby’s body and brain develop, which can cause both mental and physical challenges for the baby. Even though people with Down syndrome might act and look similar, each person has different abilities.
What causes chromosome duplication?
Duplications typically arise from an event termed unequal crossing-over (recombination) that occurs between misaligned homologous chromosomes during meiosis (germ cell formation). The chance of this event happening is a function of the degree of sharing of repetitive elements between two chromosomes.
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 deletion and duplication?
Homologous recombination between areas of concentrated repeated sequences frequently creates deletions and duplications. Because they commonly involve more than one gene, the disorders caused by these large deletion and duplication mutations are often severe.
What do you need to know about chromosome 1p duplication?
Summary Summary. Chromosome 1p duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm (p) of chromosome 1. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved.
What happens to a fetus with chromosome 1p32-p31 deletion?
Fetuses with chromosome 1p32-p31 deletion syndrome and haploinsufficiency of the NFIA gene may present ventriculomegaly, corpus callosum hypogenesis, abnormal external genitalia, and intrauterine growth restriction in the third trimester.
Which is a critical region of chromosome 1p32-p31?
A critical region for hypoplastic/absent corpus callosum and ventriculomegaly has been proposed at 1p31.3-p31.2 in a series of five patients of chromosome 1p32-p31 deletion syndrome with haploinsufficiency of the NFIA gene [1].