Biology - Genetic Diversity and adaptation

define mutation

any change to the base sequence or quantity of DNA

define gene mutation

any change to one or more nucleotide bases

define chromosomal mutation

changes in structure or number of whole chromosomes

define non-dysjunction

a change in number of chromosomes because individual chromosomes fail to separate in replication

define polyploidy

having three or more sets of chromosomes rather than two (usually in plants)

gene mutations - what is substitution of bases

nucleotide is replaced by another nucleotide with a different base

gene mutations - deletion of bases

a nucleotide is lost from the normal DNA sequence

• the amino acid sequence is usually entirely different because bases read in triplets so the deletion of one base shifts each base to the left, forming all new codons

define mutagenic agent

a factor that increases the rate of mutations

examples of mutagenic agents

• high energy radiation

• x-rays

• UV light

• carcinogens