Mutations Flashcards
Mutation
Changes in the DNA that replace, insert, or delete nucleotides
Mutations are the ultimate source of…
All new genes and the genetic diversity of life
2 main categories of mutations
1) Large Scale
2) Small Scale
Large Scale Mutations
Affect long segments of DNA
(chromosomal rearrangement)
Small Scale Mutations
Affect one or a few nucleotide pairs
Mutations can alter phenotypes by…
Impacting gene product sequence or expression
–> Altering levels of mRNA + proteins or the STRUCTURE of these molecules
Mutations in Non-Coding Regions of DNA
Don’t impact structure/function of gene products but instead alter gene expression and regulation
Most mutations are within the…
Non-coding region of DNA
Germ Cell Mutations
Inherited between generations
Somatic Cell Mutations
Not inherited
–> But can cause serious problems for people when cells with a mutation proliferate (= cancer)
What factors determine phenotypic effect of a mutation?
1) The type of cell
2) When in the life cycle the mutation occurs (the earlier the more severe its effects)
3) The dominance of a mutation
Point mutations
Changes in a single nucleotide pair of a gene (single base pair change)
2 main types of point mutations:
1) Substitutions
2) Deletions/Insertions
Substitution Mutations
The replacement of one nucleotide and its partner with another pair of nucleotides
Types of substitution mutations
1) Missense
2) Nonsense
3) Silent