Related topics: cancer , genes , protein , genetic mutations , evolution
Mutation
hideIn 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.
For more information about Mutation, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with mutations
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(PhysOrg.com) -- Life's ability to replicate itself is essential for evolution, yet even the simplest kind of replication requires a relatively complex system. So what kind of non-replicating system might ...
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Dec 16, 2009 |
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Research teams led by the Wellcome Trust Sanger Institute announce the first comprehensive analyses of cancer genomes. All cancers are caused by mutations in the DNA of cancer cells which are acquired during a person's lifetime. ...
Evolution may take giant leaps
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(PhysOrg.com) -- A new study of thousands of species of plants and animals suggests new species may arise from rare events instead of through an accumulation of small changes made in response to changes in ...
Ancient penguin DNA raises doubts about accuracy of genetic dating techniques
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Penguins that died 44,000 years ago in Antarctica have provided extraordinary frozen DNA samples that challenge the accuracy of traditional genetic aging measurements, and suggest those approaches have been ...
Study shows that some malignant tumors can be shut down after all
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Oncologists have had their hands tied because more than half of all human cancers have mutations that disable a protein called p53. As a critical anti-cancer watchdog, p53 masterminds several cancer-fighting operations within ...
Time in a bottle: Scientists watch evolution unfold
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A 21-year Michigan State University experiment that distills the essence of evolution in laboratory flasks not only demonstrates natural selection at work, but could lead to biotechnology and medical research ...
Ratchet-like genetic mutations make evolution irreversible
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(PhysOrg.com) -- A University of Oregon research team has found that evolution can never go backwards, because the paths to the genes once present in our ancestors are forever blocked. The findings -- the ...
Two more genetic risk factors for Alzheimer's disease found
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An international team of scientists has identified two more genetic risk factors for Alzheimer's disease. The findings are reported in the online edition of the journal Nature Genetics.
We are all mutants: Measurement of mutation rate in humans by direct sequencing
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An international team of 16 scientists today reports the first direct measurement of the general rate of genetic mutation at individual DNA letters in humans. The team sequenced the same piece of DNA - 10,000,000 or so letters ...
First human gene implicated in regulating length of human sleep
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Scientists have discovered the first gene involved in regulating the optimal length of human sleep, offering a window into a key aspect of slumber, an enigmatic phenomenon that is critical to human physical and mental health.
Professor sequences his entire genome at low cost, with small team
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(PhysOrg.com) -- The first few times that scientists mapped out all the DNA in a human being in 2001, each effort cost hundreds of millions of dollars and involved more than 250 people. Even last year, when ...
'Sloppier copier' surprisingly efficient
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The "sloppier copier" discovered by USC biologists is also the best sixth man in the DNA repair game, an article in the journal Nature shows.
In Ocean's Depths, Heat-Loving 'Extremophile' Evolves a Strange Molecular Trick
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(PhysOrg.com) -- Making its home near extreme temperatures of thermal vents on the ocean floor, the organism Methanopyrus kandleri harbors a molecular secret that intrigues evolutionary biologists and even ...
'Personalized' genome sequencing reveals coding error in gene for inherited pancreatic cancer
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Scientists at the Sol Goldman Pancreatic Cancer Research Center at the Johns Hopkins Kimmel Cancer Center have used "personalized genome" sequencing on an individual with a hereditary form of pancreatic cancer to locate a ...
Newly discovered gene plays vital role in cancer
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(PhysOrg.com) -- Gene p53 protects against cancer and is usually described as the most important gene in cancer research. However, scientists at the Swedish medical university Karolinska Institutet have now shown that a previously ...
