The gametic (n) and somatic (2n) chromosome numbers remain constant in a species due to the correct mitotic and meiotic cell divisions. Gametes in a diploid organism possess only a single copy of each chromosome, however, somatic cells possess two copies of each chromosome.
The genomes of chromosomes are different in terms of their morphology and genetic content. However, homologous chromosomes genomes are identical and contain similar genes in the same sequence. Rarely, some spontaneous variations occur in chromosomes. These variations are known as genetic mutations.
In other words, a genetic mutation is defined as a permanent change in the genetic sequence that make up a gene. Genetic mutation can take place in two dissimilar ways: they can either be passed from a parent or acquired during a person’s life span. A mutation that is inherited from parents to child is called a germline mutation that involves the egg and sperm cells. Acquired mutations, on the other hand, occur in the DNA of each cell during a person’s life span. These variations can be influenced by environmental factors, including ultraviolet radiation from the sun, or DNA mismatch during cell division.
Following are additional facts about chromosomal mutations.
In addition, mutation can also take place inside an early embryo, but this may happen in a single cell. When each cell of the embryo divides, the individual will have some both mutated cells and normal cells.