Describe the main types of gene, chromosomal and genomic mutations.

– Gene mutations – changes in the nucleotide sequence of DNA within a single gene. This is the most common type of mutation and the most important source of hereditary variability of organisms. Gene mutations include insertions, prolapse, and nucleotide substitutions.
– Chromosomal mutations are changes in the structure of chromosomes. There are intrachromosomal and interchromosomal mutations. Intrachromosomal mutations include: loss of a chromosome region (deletion), double or multiple repetition of a chromosome fragment (duplication), rotation of the chromosome region by 180 ° (inversion). Interchromosomal mutations include the exchange of sites between two non-homologous chromosomes (translocation).
– Genomic mutations are a change in the number of chromosomes in cells. Among genomic mutations, polyploidy and heteroploidy are distinguished.
Polyploidy is an increase in the number of chromosomes in cells that is a multiple of the haploid set. For example, 3n (triploidy), 4n (tetraploidy), 6n (hexaploidy), 8n (octaploidy). Polyploidy is distributed mainly in plants. Polyploid forms have large leaves, flowers, fruits and seeds, are characterized by increased resistance to adverse environmental factors.
Heteroploidy (aneuplodia) is a change in the number of chromosomes that is not a multiple of the haploid set. For example, 2n – 2 (nullisomy if there is no pair of homologous chromosomes), 2n – 1 (monosomy), 2n + 1 (trisomy), 2n + 2 (tetrasomy), 2n + 3 (pentasomy).