Mutations I

Mutation

A change in the genetic material of a cell or virus.

Genes

Genomic sequences (DNA or RNA) that directly encode functional product molecules, either RNA or protein.

Spontaneous mutation

Natural genetic changes occurring at a low rate, crucial for evolution.

Natural selection

The process that requires genetic differences generated by recombination and spontaneous mutation.

De novo mutations

New mutations that appear for the first time in an individual.

Replication/repair error

Errors that occur during the process of DNA replication or repair, which can lead to mutations.

Reactive O2 species (ROS)

Unstable molecules containing oxygen that can react easily with other molecules and potentially cause mutations.

Net mutation

The result of DNA damage minus successful repair attempts.

Germ line cells

Sperm or egg cells that can pass mutations to the next generation.

Somatic cells

Body cells that do not contribute to the germline and have higher mutation rates that are not inherited.

Effects of mutations

The majority of mutations have no effect due to their location in the genome.

Point mutations

Mutations that affect a single nucleotide; types include silent, nonsense, missense, and frameshift.

Recessive mutations

Mutations that do not affect the phenotype unless in a homozygous genotype.

Homozygous

Having two identical alleles for a specific gene.

Inbreeding

The mating of individuals who are closely related, which can increase the chance of recessive mutations expressing phenotypically.