How does spontaneous genetic mutation occur?

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 is spontaneous mutation in plants?

Spontaneous mutations are alleles of initially unknown genes and are given allele names and symbols based on their phenotype (e.g. diabetes, db).

How do genetic mutations occur in plants?

Changes in the genetic code occur randomly and can happen when mistakes are made during cell division and replication, after exposure to radiation or certain chemicals or because of weather fluctuations such as extreme cold or heat. Insect damage or severe pruning also can cause a mutation in plants.

What is spontaneous mutation and gene mutation briefly?

Spontaneous mutations can occur because of replication errors or as a consequence of lesions introduced into DNA during normal cell growth. Induced mutations arise after treatment of the organism with an exogenous mutagen being physical or chemical agent increasing the frequency of mutations.

When do random or spontaneous mutations happen?

Current research suggests most spontaneous mutations occur as errors in the repair process for damaged DNA. Neither the damage nor the errors in repair have been shown to be random in where they occur, how they occur, or when they occur.

What is an example of a spontaneous mutation?

One example of spontaneous mutation is the appearance of sickle cell anemia in humans. It occurs naturally, and it has stuck around for new generations because it is beneficial to carry the sickle cell anemia gene in areas with high incidence of malaria.

What does spontaneous mutation mean in biology?

A mutation occurring in the absence of mutagens, usually due to errors in the normal functioning of cellular enzymes.

What are sources of genetic variation in plant breeding?

Overall, the main sources of genetic variation are the formation of new alleles, the altering of gene number or position, rapid reproduction, and sexual reproduction.

Why is genetic diversity important for plants?

Genetic diversity is of fundamental importance in the continuity of a species as it provides the necessary adaptation to the prevailing biotic and abiotic environmental conditions, and enables change in the genetic composition to cope with changes in the environment. …

What is spontaneous mutation in biology?

A ‘naturally’ occurring mutation in the absence of a mutagen that would otherwise be a known factor for inducing a particular mutation.

What causes spontaneous and induced mutations?

How does mutation cause genetic variation?

The flow of individuals in and out of a population introduces new alleles and increases genetic variation within that population. Mutations are changes to an organism’s DNA that create diversity within a population by introducing new alleles.

What happens when a mutation occurs in a plant cell?

Some mutations can be unstable and result in producing sections of the plant that revert to their original state (Photo 2). Plant point mutations are often found after stressful environmental conditions, especially cold. All cells in an organism contain the same genetic information no matter their location.

What is the main cause of spontaneous mutations?

A common cause of spontaneous mutations is deamination, in which the amino group on the number 2 carbon of cytosine (C) is removed, converting C to uracil (U) in DNA. Another cause is copying errors during DNA replication: slippage or shifting of the translational reading frame.

How are spontaneous mutants selected for cultivation?

For many years, spontaneous mutants have been selected by farmers and breeders, propagated and grown as new cultivars.

What causes mutations in the genetic code?

Changes in the genetic code occur randomly and can happen when mistakes are made during cell division and replication, after exposure to radiation or certain chemicals or because of weather fluctuations such as extreme cold or heat. Insect damage or severe pruning also can cause a mutation in plants. Fasciation in plants is a good example.