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Changes in DNA caused by mutation in a coding region of DNA can cause errors in protein sequence that may result in partially or completely non-functional proteins. Each cell, in order to function correctly, depends on thousands of proteins to function in the right places at the right times.
Long-term effects can be a permanent changing of a chromosome, which can lead to a mutation. These mutations can be either beneficial or detrimental. Cancer is an example of how they can be detrimental. [6] Other effects of point mutations, or single nucleotide polymorphisms in DNA, depend on the location of the mutation within the gene.
Transversion, in molecular biology, refers to a point mutation in DNA in which a single (two ring) purine (A or G) is changed for a (one ring) pyrimidine (T or C), or vice versa. [1] A transversion can be spontaneous, or it can be caused by ionizing radiation or alkylating agents. It can only be reversed by a spontaneous reversion.
This is an uncommon occurrence that depends on the type of mutants being investigated. Two mutations, for example, could be synthetically dominant negative. Transvection is another instance, in which a heterozygous combination of two alleles with mutations in distinct sections of the gene complement one other to restore a wild-type phenotype. [7]
Mutations followed by expansion would result in the formation of new types of adjacent short tandem repeat units. For example, a transversion could change the simple two- base repeat [GA] 10 to [GA] 4 GATA[GA] 2. This could then be expanded to[GA] 4 [GATA] 3 [GA] 2 by two subsequent SSM events.
Mutations in these sequences may lead to retention of large segments of intronic DNA by the mRNA, or to entire exons being spliced out of the mRNA. These changes could result in production of a nonfunctional protein. [2] An intron is separated from its exon by means of the splice site.
[2] DNA damage and mutation have different biological consequences. While most DNA damages can undergo DNA repair, such repair is not 100% efficient. Un-repaired DNA damages accumulate in non-replicating cells, such as cells in the brains or muscles of adult mammals, and can cause aging.
They can affect the transcription and replication of the DNA, which in severe cases can lead to cell death. The mutagen produces mutations in the DNA, and deleterious mutation can result in aberrant, impaired or loss of function for a particular gene, and accumulation of mutations may lead to cancer. Mutagens may therefore be also carcinogens.