Duplications may affect phenotype by altering gene dosage. For example, the amount of protein synthesized is often proportional to the number of gene copies present, so extra genes can lead to excess proteins.
How can gene duplication affect gene expression?
Most of the new-born duplicates lead to increased expression and are costly for the cell. So far, we have demonstrated that a duplicated gene offers a selective advantage provided the total gene expression level is maintained, with one or two copies (gene dosage sharing).
Is gene duplication good or bad?
Duplicate genes are not only redundant, but they can be bad for cells. Most duplicate genes accumulate mutations at high rates, which increases the chance that the extra gene copies will become inactive and lost over time due to natural selection.
What is the importance of duplication?
Gene duplication is an important mechanism for acquiring new genes and creating genetic novelty in organisms. Many new gene functions have evolved through gene duplication and it has contributed tremendously to the evolution of developmental programmes in various organisms.
How often does MECP2 duplication syndrome occur?
Well over 200 individuals have been reported in the medical literature. It has been estimated that approximately 1-2% of unexplained cases of X-linked intellectual disability may be due to MECP2 duplication syndrome.
What is an example of duplication mutation?
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.
Can duplication syndrome be inherited?
In most cases, MECP2 duplication syndrome is inherited from a mother who carries the duplication but has no symptoms. Rarely, the condition is not inherited. In these cases it may occur randomly during the formation of the egg or sperm, or shortly after the egg and sperm join together.
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 the importance of gene duplication in molecular evolution?
Gene and genome duplications provide a source of genetic material for mutation, drift, and selection to act upon, making new evolutionary opportunities possible. As a result, many have argued that genome duplication is a dominant factor in the evolution of complexity and diversity.
What were the first genes on Earth?
Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects.