Substances

• Carcinogens.
• Ethylene Dichlorides.
• Flame Retardants.
• Hair Dyes.
• Hydrocarbons, Halogenated.
• Mutagens.
• Furylfuramide.
• Ethylene Dibromide. DNA.

​Mutation. A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.

Physical mutagens include electromagnetic radiation, such as gamma rays, X rays, and UV light, and particle radiation, such as fast and thermal neutrons, beta and alpha particles. Mutagenic treatment of seeds is the most convenient and, therefore, the standard method in seed propagated crops.

A mutagen is a chemical or physical agent that has the ability to change our genetic code in a harmful way. The change in the genetic code is called a mutation, and throughout our lifetime we actually accumulate many mutations within our cells.

Anything that causes a mutation (a change in the DNA of a cell). DNA changes caused by mutagens may harm cells and cause certain diseases, such as cancer. Examples of mutagens include radioactive substances, x-rays, ultraviolet radiation, and certain chemicals.

Two major categories of mutations are germline mutations and somatic mutations. Germline mutations occur in gametes. These mutations are especially significant because they can be transmitted to offspring and every cell in the offspring will have the mutation.

There are three types of DNA Mutations: base substitutions, deletions and insertions.

• Base Substitutions. Single base substitutions are called point mutations, recall the point mutation Glu —–> Val which causes sickle-cell disease.
• Deletions.
• Insertions.

by admin | Jun 29, 2016. A change in the DNA that can truncate or shorten the protein. [showmodule id=”520″]

The same disease may, however, be caused by other kinds of damage to the same gene. Examples of diseases in which nonsense mutations are known to be among the causes include: Cystic fibrosis (caused by the G542X mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) Beta thalassaemia (β-globin)

A nonsense mutation is a genetic mutation in a DNA sequence that results in a shorter, unfinished protein product. Stop codons are also called nonsense codons because they do not code for an amino acid and instead signal the end of protein synthesis.

A change in the DNA that does not truncate or shorten the protein.

Effects of Mutations A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations with small effects. Mutational effects can be beneficial, harmful, or neutral, depending on their context or location. Most non-neutral mutations are deleterious.

two types

Deletion is a type of mutation involving the loss of genetic material. It can be small, involving a single missing DNA base pair, or large, involving a piece of a chromosome.

Phenotypic effects of deletions depend on the size and location of deleted sequences on the genome. For instance, deletions that span a centromere result in an acentric chromosome that will most likely be lost during cell division. As with duplications, deletions can affect gene dosage and thus the resulting phenotype.

When parts of chromosomes are missing, a number of syndromes can occur. These syndromes are called chromosomal deletion syndromes. They tend to cause birth defects and limited intellectual development and physical development. In some cases, defects can be severe and affected children die during infancy or childhood.

A deletion changes the DNA sequence by removing at least one nucleotide in a gene. Small deletions remove one or a few nucleotides within a gene, while larger deletions can remove an entire gene or several neighboring genes. The deleted DNA may alter the function of the affected protein or proteins.

When you delete a file from a standard desktop computer, the file first gets moved to the “recycle bin” or the “trash,” which means only that you’ve placed the intact data in a new directory. You erase the file when you empty your recycle bin. But even then, much of the information remains on the hard disk.

Click any image for a full-size version.

1. Press the Windows Button + R to open the “Run” dialog box.
2. Enter this text: %temp%
3. Click “OK.” This will open your temp folder.
4. Press Ctrl + A to select all.
5. Press “Delete” on your keyboard and click “Yes” to confirm.
6. All temporary files will now be deleted.

1. To nominate a page, place the {{subst:Proposed deletion|concern=reason for proposed deletion}} tag at the top of the page.
2. If anybody objects to the deletion (usually by removing the {{proposed deletion/dated}} tag—see full instructions below), the proposal is aborted and may not be re-proposed.

Deletion of a Wikipedia article removes the current version and all previous versions from public view. Page blanking can be performed (or reverted) by any user, but only administrators can perform deletion, view deleted pages, and reverse (“undelete”) any deletion.

Speedy deletion is intended to reduce the time spent on deletion discussions for pages or media with no practical chance of surviving discussion.

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A sysop (/ˈsɪsɒp/; an abbreviation of system operator) is an administrator of a multi-user computer system, such as a bulletin board system (BBS) or an online service virtual community. The phrase may also be used to refer to administrators of other Internet-based network services.