Neuroscience

Genetic malfunction of brain astrocytes triggers migraine

Neuroscientists of the University of Zurich shed a new light on the mechanisms responsible for familial migraine: They show that a genetic dysfunction in specific brain cells of the cingulate cortex area strongly influences ...

Genetics

Researchers identify new genetic defect linked to ALS

Researchers at the University of Maryland School of Medicine (UMSOM) have identified how certain gene mutations cause amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. The pathway identified by the ...

Diseases, Conditions, Syndromes

Mutating coronavirus: what it means for all of us

An important milestone in the fight against COVID-19 came in early January 2020, when the entire viral genome of the novel coronavirus that causes the diseasewas sequenced for the first time. Since then, the full coronavirus ...

Oncology & Cancer

Inherited mutation found among Brazilians increases cancer risk

Scientists at St. Jude Children's Research Hospital alongside global partners are studying a common TP53-R337H variant found among people of Brazilian descent. The researchers found that a variant in the tumor suppressor ...

Genetics

New method created for identifying genes behind brain tumors

Researchers at Uppsala University have developed a method for identifying functional mutations and their effect on genes relevant to the development of glioblastoma—a malignant brain tumor with a very poor prognosis. The ...

Oncology & Cancer

Blood cancer find raises new treatment hopes

New QIMR Berghofer research has identified how an early genetic change in blood and bone marrow cells paves the way for the development of some blood cancers.

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Mutation

In biology, mutations are changes to the nucleotide sequence of the genetic material of an organism. Mutations can be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or viruses, or can be induced by the organism itself, by cellular processes such as hypermutation. In multicellular organisms with dedicated reproductive cells, mutations can be subdivided into germ line mutations, which can be passed on to descendants through the reproductive cells, and somatic mutations, which involve cells outside the dedicated reproductive group and which are not usually transmitted to descendants. If the organism can reproduce asexually through mechanisms such as cuttings or budding the distinction can become blurred. For example, plants can sometimes transmit somatic mutations to their descendants asexually or sexually where flower buds develop in somatically mutated parts of plants. A new mutation that was not inherited from either parent is called a de novo mutation. The source of the mutation is unrelated to the consequence, although the consequences are related to which cells were mutated.

Mutations create variation within the gene pool. Less favorable (or deleterious) mutations can be reduced in frequency in the gene pool by natural selection, while more favorable (beneficial or advantageous) mutations may accumulate and result in adaptive evolutionary changes. For example, a butterfly may produce offspring with new mutations. The majority of these mutations will have no effect; but one might change the color of one of the butterfly's offspring, making it harder (or easier) for predators to see. If this color change is advantageous, the chance of this butterfly surviving and producing its own offspring are a little better, and over time the number of butterflies with this mutation may form a larger percentage of the population.

Neutral mutations are defined as mutations whose effects do not influence the fitness of an individual. These can accumulate over time due to genetic drift. It is believed that the overwhelming majority of mutations have no significant effect on an organism's fitness. Also, DNA repair mechanisms are able to mend most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells.

Mutation is generally accepted by the scientific community as the mechanism upon which natural selection acts, providing the advantageous new traits that survive and multiply in offspring or disadvantageous traits that die out with weaker organisms.

This text uses material from Wikipedia, licensed under CC BY-SA