Mutation, Natural Selection, and Artificial Selection

Mutation is a change in DNA sequence Change in DNA  change in protein  change in organism Mutation can be positive, negative or neutral. Mutagen: a physical or chemical agent that changes the DNA

Types of Mutations Gene change in the nucleotide sequence, in a particular gene 2. Chromosomal is a change in several genes segments of chromosomes, whole chromosomes, or entire sets of chromosomes change

Gene Mutations Types: Point mutation change in ONE nucleotide base of the DNA sequence The change in the DNA is minor but important Ex) Substitution – change of one base to another base

2. Frameshift Mutation a single base is added or deleted from DNA which shifts the reading of codons by one base. The results of frameshift mutations can be HUGE since every codon after the mistake is affected! Ex) Insertion – one base is added Ex) Deletion – one base is removed

Chromosomal Mutations 4 main types: Deletion: part of a chromosome left out Insertion: additions to a chromosome Inversion: chromosome part breaks off & reattaches backwards Translocation: chromosome part breaks off & adds to another chromosome

Mutation can be positive, negative or neutral. Positive: antibiotic resistance in bacteria increases survival

Negative: duplication of codons in Huntington’s disease gene causes the protein to work incorrectly, decreasing survival

Neutral: change in DNA that does not cause a change in protein (silent) or changes something that does not affect survival

Can depend on environment whether a mutation is +, -, or neutral Ex. Sickle Cell Anemia