who knows any interesting fact about mutations?

In biology, mutations are changes to the base pair 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 occur deliberately under cellular control during processes such as hypermutation. In multicellular organisms, mutations can be subdivided into germ line mutations, which can be passed on to descendants, and somatic mutations, which cannot be transmitted to descendants in animals. Plants sometimes can transmit somatic mutations to their descendants asexually or sexually (in case when flower buds develop in somatically mutated part of plant). A new mutation that was not inherited from either parent is called a de novo mutation.

Mutations create variations in the gene pool, and the less favorable (or deleterious) mutations are reduced in frequency in the gene pool by natural selection, while more favorable (beneficial or advantageous) mutations tend to accumulate, resulting in evolutionary change. For example, a butterfly may produce offspring with a new mutation. Many times new mutations are harmful; a new mutation 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 an advantage, the chances 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 either the species or the individuals who make up the species. These can accumulate over time due to genetic drift. The overwhelming majority of mutations have no significant effect, since DNA repair is able to mend most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells.

By effect on structure

The sequence of a gene can be altered in a number of ways. Gene mutations have varying effects on health depending on where they occur and whether they alter the function of essential proteins. Structurally, mutations can be classified as:

Small-scale mutations, such as affecting a small gene is one or a few nucleotides, including:

Point mutations, often caused by chemicals or malfunction of DNA replication, exchange a single nucleotide for another. Most common is the transition that exchanges a purine for a purine (A ↔ G) or a pyrimidine for a pyrimidine, (C ↔ T). A transition can be caused by nitrous acid, base mis-pairing, or mutagenic base analogs such as 5-bromo-2-deoxyuridine (BrdU). Less common is a transversion, which exchanges a purine for a pyrimidine or a pyrimidine for a purine (C/T ↔ A/G). A point mutation can be reversed by another point mutation, in which the nucleotide is changed back to its original state (true reversion) or by second-site reversion (a complementary mutation elsewhere that results in regained gene functionality). These changes are classified as transitions or transversions. An example of a transversion is adenine (A) being converted into a cytosine (C). There are also many other examples that can be found. Point mutations that occur within the protein coding region of a gene may be classified into three kinds, depending upon what the erroneous codon codes for:

Silent mutations: which code for the same amino acid.

Missense mutations: which code for a different amino acid.

Nonsense mutations: which code for a stop and can truncate the protein.

Insertions add one or more extra nucleotides into the DNA. They are usually caused by transposable elements, or errors during replication of repeating elements (e.g. AT repeats). Insertions in the coding region of a gene may alter splicing of the mRNA (splice site mutation), or cause a shift in the reading frame (frameshift), both of which can significantly alter the gene product. Insertions can be reverted by excision of the transposable element.

Deletions remove one or more nucleotides from the DNA. Like insertions, these mutations can alter the reading frame of the gene. They are irreversible.

Large-scale mutations in chromosomal structure, including:

Amplifications (or gene duplications) leading to multiple copies of all chromosomal regions, increasing the dosage of the genes located within them.

Deletions of large chromosomal regions, leading to loss of the genes within those regions.

Mutations whose effect is to juxtapose previously separate pieces of DNA, potentially bringing together separate genes to form functionally distinct fusion genes (e.g. bcr-abl). These include:

Chromosomal translocations: interchange of genetic parts from nonhomologous chromosomes.

Interstitial deletions: an intra-chromosomal deletion that removes a segment of DNA from a single chromosome, thereby apposing previously distant genes. For example, cells isolated from a human astrocytoma, a type of brain tumor, were found to have a chromosomal deletion removing sequences between the "fused in glioblastoma" (fig) gene and the receptor tyrosine kinase "ros", producing a fusion protein (FIG-ROS). The abnormal FIG-ROS fusion protein has constitutively active kinase activity that causes oncogenic transformation (a transformation from normal cells to cancer cells).

Chromosomal inversions: reversing the orientation of a chromosomal segment.

Loss of heterozygosity: loss of one allele, either by a deletion or recombination event, in an organism that previously had two different alleles.

[edit] By effect on function

Loss-of-function mutations are the result of gene product having less or no function. When the allele has a complete loss of function (null allele) it is often called an amorphic mutation. Phenotypes associated with such mutations are most often recessive. Exceptions are when the organism is haploid, or when the reduced dosage of a normal gene product is not enough for a normal phenotype (this is called haploinsufficiency).

Gain-of-function mutations change the gene product such that it gains a new and abnormal function. These mutations usually have dominant phenotypes. Often called a neo-morphic mutation.

Dominant negative mutations (also called anti-morphic mutations) have an altered gene product that acts antagonistically to the wild-type allele. These mutations usually result in an altered molecular function (often inactive) and are characterised by a dominant or semi-dominant phenotype. In humans, Marfan syndrome is an example of a dominant negative mutation occurring in an autosomal dominant disease. In this condition, the defective glycoprotein product of the fibrillin gene (FBN1) antagonizes the product of the normal allele.

Lethal mutations are mutations that lead to a phenotype incapable of effective reproduction.

[edit] By aspect of phenotype affected

Morphological mutations usually affect the outward appearance of an individual. Mutations can change the height of a plant or change it from smooth to rough seeds.

Biochemical mutations result in lesions stopping the enzymatic pathway. Often, morphological mutants are the direct result of a mutation due to the enzymatic pathway.

[edit] By inheritance

The human genome contains two copies of each gene- a paternal and a maternal allele.

Wildtype or Homozygous non-mutated is when neither alleles are mutated.

A Heterozygous mutation is when only one allele is mutated.

A Homozygous mutation is when both the paternal and maternal alleles have an identical mutation.

Compound heterozygous mutations or a Genetic compound is when the paternal and maternal alleles have two different mutations.

Special classes

Conditional mutation is a mutation that has wild-type (or less severe) phenotype under certain "permissive" environmental conditions and a mutant phenotype under certain "restrictive" conditions. For example, a temperature-sensitive mutation can cause cell death at high temperature (restrictive condition), but might have no deleterious consequences at a lower temperature (permissive condition).

Causes of mutation

Two classes of mutations are spontaneous mutations (molecular decay) and induced mutations caused by mutagens.

Spontaneous mutations on the molecular level include:

Tautomerism - A base is changed by the repositioning of a hydrogen atom.

Depurination - Loss of a purine base (A or G).

Deamination - Changes a normal base to an atypical base; C → U, (which can be corrected by DNA repair mechanisms), or spontaneous deamination of 5-methycytosine (irreparable), or A → HX (hypoxanthine).

Transition - A purine changes to another purine, or a pyrimidine to a pyrimidine.

Transversion - A purine becomes a pyrimidine, or vice versa.

Benzopyrene, the major mutagen in tobacco smoke, in an adduct to DNA. Produced from PDB 1JDG.Induced mutations on the molecular level can be caused by:

Chemicals

Nitrosoguanidine (NTG)

Hydroxylamine NH2OH

Base analogs (e.g. BrdU)

Simple chemicals (e.g. acids)

Alkylating agents (e.g. N-ethyl-N-nitrosourea (ENU)) These agents can mutate both replicating and non-replicating DNA. In contrast, a base analog can only mutate the DNA when the analog is incorporated in replicating the DNA. Each of these classes of chemical mutagens has certain effects that then lead to transitions, transversions, or deletions.

Methylating agents (e.g. ethyl methanesulfonate (EMS))

Polycyclic hydrocarbons (e.g. benzopyrenes found in internal combustion engine exhaust)

DNA intercalating agents (e.g. ethidium bromide)

DNA crosslinker (e.g. platinum)

Oxidative damage caused by oxygen(O)] radicals

Radiation

Ultraviolet radiation (nonionizing radiation) - excites electrons to a higher energy level. DNA absorbs one form, ultraviolet light. Two nucleotide bases in DNA - cytosine and thymine-are most vulnerable to excitation that can change base-pairing properties. UV light can induce adjacent thymine bases in a DNA strand to pair with each other, as a bulky dimer.

Ionizing radiation

DNA has so-called hotspots, where mutations occur up to 100 times more frequently than the normal mutation rate. A hotspot can be at an unusual base, e.g., 5-methylcytosine.

Mutation rates also vary across species.

Evolutionary biologists have theorized that higher mutation rates are beneficial in some situations, because they allow organisms to evolve and therefore adapt more quickly to their environments. For example, repeated exposure of bacteria to antibiotics, and selection of resistant mutants, can result in the selection of bacteria that have a much higher mutation rate than the original population (mutator strains).

1.) The planet Mercury has a longer day than it does a year. 2.) The Vulcan race in Star Trek is named after a possibly 10th planet. One that is closer to the sun than Mercury. Some Astronomers have claimed to have seen it while the ones that count simply call it a myth. 3.) In Spanish, all the days of the week are named after Roman gods/planets: Lunes (Luna), Martes (Mars), Mercoles (Mercury), Jueves (Jupiter), Viernes (Venus), Sabato (Saturn), Domedica (Sun). 4.) There is a Super Volcano underneath Yellowstone National Park. Its eruption date is overdue. 5.) In World War II, Hitler had his soldiers dress up in Polish military uniforms and open fire on German land. Therefor he could use that to justify the attack on Poland. 6.) Ice trays freeze faster with hot water rather than cold water. 7.) When the Roman calendar was first adopted off the Greek calendar, July and August (The months dedicated to Caeser were the final two.

For one, it's caused by an "error" in cell replication in the embryonic stage of human development.

try Sickle Cell Anemia Foundation and Cytic Fibrosis Foundation.

I know one interesting fact about Sickle cell anemia in assocation with malaria. If you have anemia you are immune to malaria due the fact that anemia puts that sickle shape sell in ypour bllod cells and the female misquitoes can't deposit her eggs in it, I think.

mutation is when things change appearance, mutation is enhanced by the suns UV rays

tv shows and movies like x-men and heroes are good references.. also try wikipedia.com...it complete of all the facts that you needed

they look different

psh.