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In genetics, it is sometimes useful to classify mutations as either harmful or beneficial (or neutral): A harmful, or deleterious, mutation decreases the fitness of the organism. Many, but not all mutations in essential genes are harmful (if a mutation does not change the amino acid sequence in an essential protein, it is harmless in most cases ...
The international pictogram for chemicals that are sensitising, mutagenic, carcinogenic or toxic to reproduction. In genetics, a mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level.
In nature, the mutations that arise may be beneficial or deleterious—this is the driving force of evolution. An organism may acquire new traits through genetic mutation, but mutation may also result in impaired function of the genes and, in severe cases, causes the death of the organism.
There are several methods, or forms, of mutation that exist including spontaneous mutation, errors during replication and repair, as well as mutation due to environmental effects. [8] These origins of mutations can cause many different types of mutations which influence gene expression on both large and small scales.
Mutations can lead to phenotypic effects such as loss-of-function, gain-of-function, and conditional mutations. [72] Some mutations are beneficial, as they are a source of genetic variation for evolution. [72] Others are harmful if they were to result in a loss of function of genes needed for survival. [72]
The extreme endpoint of this distribution are the so-called 'monogenic' obesities where most of the impact on body weight can be tied to a mutation in a single gene that runs in a single family. The classic example of such a genetic effect is the presence of mutations in the leptin gene.
Missense mutations and nonsense mutations are examples of point mutations that can cause genetic diseases such as sickle-cell disease and thalassemia respectively. [ 38 ] [ 39 ] [ 40 ] Clinically important missense mutations generally change the properties of the coded amino acid residue among basic, acidic, polar or non-polar states, whereas ...
Point germline mutations can lead to beneficial as well as harmful traits or diseases. This leads to adaptations based on the environment where the organism lives. An advantageous mutation can create an advantage for that organism and lead to the trait's being passed down from generation to generation, improving and benefiting the entire ...