What is an example of a spontaneous mutation?
Spontaneous mutations in mice may result in benign phenotypes, such as variable coat colors, or in disorders that have similarities to diseases in man, for example, the hyperphosphatemia (Hyp) mouse, which is representative of X-linked hyperphosphatemia in man.
What is the spontaneous mutation?
A ‘naturally’ occurring mutation in the absence of a mutagen that would otherwise be a known factor for inducing a particular mutation.
What is an example of a human disease caused by a substitution mutation?
Types of Changes in DNA
|Class of Mutation||Type of Mutation||Human Disease(s) Linked to This Mutation|
|Point mutation||Substitution||Sickle-cell anemia|
|Insertion||One form of beta-thalassemia|
|Chromosomal mutation||Inversion||Opitz-Kaveggia syndrome|
What are 3 gene mutations that occur in humans?
There are three types of DNA Mutations: base substitutions, deletions and insertions.
What causes spontaneous mutation?
Mutations arise spontaneously at low frequency owing to the chemical instability of purine and pyrimidine bases and to errors during DNA replication. Natural exposure of an organism to certain environmental factors, such as ultraviolet light and chemical carcinogens (e.g., aflatoxin B1), also can cause mutations.
What causes random mutation?
What diseases are caused by a deletion mutation?
Deletions are responsible for an array of genetic disorders, including some cases of male infertility, two thirds of cases of Duchenne muscular dystrophy, and two thirds of cases of cystic fibrosis (those caused by ΔF508). Deletion of part of the short arm of chromosome 5 results in Cri du chat syndrome.
What are the 2 main types of mutations?
There are a variety of types of mutations. 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.
When does a tautomeric shift cause a mutation?
Tautomeric shifts causing mutations. The rare, less stable tautomeric forms of base exist for only very short periods of time.
How are tautomers produced in a DNA chain?
Tautomers are the alternate forms of bases and are produced by rearrangements of electrons and protons in the molecules (Fig. 6.46). Tautomerism is caused by certain chemical mutagens. In the next replication purines pair with pyrimidines and the base pair is altered at a particular locus.
Which is the rarest form of a tautomeric base?
The rare, less stable tautomeric forms of base exist for only very short periods of time. However, if a base existed in the rare form at the moment that it was being replicated or being incorporated into a nascent DNA chain, a mutation might result: the rare imino or enol bases can form adenine-cytosine and Guanine-Thymine base pairs.
Which is an uncommon form of tautomerisation?
The uncommon forms are unstable and at the next replication, cycle revert back to their normal forms. Due to tautomerisation the amino (-NH 2) group of cytosine and adenine is converted into imino (-NH) group and likewise keto (C=0) of thymine and guanine is converted to enol group (-OH).