Mutations Flashcards
Mutations are
Changes in the nucleotide sequence of the DNA
- Occur in body cells
- passed onto daughter cells during mitosis
- not passed on to sexually produced offspring
Somatic mutations
- occurs in the cells of the germ line
- passed on to new organism at fertilization
Germline mutations
Total DNA sequence present in all of its chromosomes
Genome
Sequence in protein coding genes within the transcribed region that are translated
Coding region
- do not affect gene function
- most mutations in large genomes
Silent mutations
Can result in either the loss of expression of a gene or in the production of a nonfunctional protein or RNA
Loss-of-function mutations
- Leads to a protein with an altered function
- usually shows dominant inheritance
- common in cancer
Gain-of-function mutations
Cause their phenotype only under certain restrictive conditions
Conditional mutations
Results from the gain, loss, or substitution of a single nucleotide
Point mutation
Extensive changes in the chromosomal structure
Chromosomal mutations
Point mutations can arise from ..
- DNA replication errors not corrected during proofreading
- Environmental mutagens
What are the four type of chromosomal mutations?
Deletions, inversions, duplications, and translocations
Removal in part of the genetic material
Deletions
Homologous chromosomes break at different positions and reconnect to the wrong partners, results in one chromosome to have 2 copies of a segment of DNA
Duplications
