Mutation notes
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Mutations are changes or alterations in the DNA sequence that can disrupt genes and alter protein production. Mutations can occur during sexual or asexual reproduction and be inherited or non-inherited. Causes of mutation include heredity, carcinogens like chemicals and radiation, and chance mistakes during DNA replication. Major types of mutations include transposons that insert into chromosomes, crossover failures in meiosis, and single gene mutations like substitutions where nucleotides are replaced or deletions where nucleotides are removed. The results of mutations can include genetic variation and hereditary disorders or cancer depending on if they are inherited or non-inherited.
Mutation notes
- 1. Mutation & Genetic Variation
- 2. I. MUTATION & GENETIC VARIATION 1. Mutation: a CHANGE or alteration of the DNA sequence that can cause a disruption of a gene and in turn alter the production of a protein
- 3. a. Mutation can involve the ENTIRE chromosome or a SINGLE gene b. May HELP, HARM, or have LITTLE to no effect on future generations o Changes may be SILENT or may cause phenotypic changes
- 4. c. Can occur during SEXUAL and ASEXUAL reproduction • _INHERITED mutation: occur in gametes and can be passed down to offspring cells – Happens during meiosis • _NONINHERITED mutation: occur in somatic cells which can alter the future new cells – Happens during mitosis!
- 5. II. CAUSES OF MUTATION: 1. _HEREDITY 2. _CARCINOGENS: chemicals, radiation, smoking, alcohol, etc. 3. _CHANCE: mistakes that happen during replication but are rare
- 6. III. MAJOR EXAMPLES THAT CAUSE MUTATIONS: 1. _JUMPING GENES: a TRANSPOSON or segment of DNA that can insert itself into different positions along a chromosome
- 7. 2. _CROSSING OVER fails: incomplete separation of chromosomes leads to more or less chromosomes in new progeny (happens in meiosis)
- 8. 3. SINGLE GENE MUTATIONS a. SUBSTITUTION: ONE or MORE nucleotides are REPLACED by a different nucleotide in the gene sequence ex: AGA copied as AGG Results in a NEW CODON (mRNA) If codon is the same as the original, the protein will not be affected ex: UCU and UCC both code for same amino acid If codon is a “stop” or different amino acid the protein will be altered
- 10. Ex: Normal: EAT THE CAT Mutation: EAT THE BAT
- 11. b. DELETION: _ONE or MORE nucleotides may be DELETED from the gene sequence o More serious consequences than substitutions o The deletion of a single nucleotide cause remaining nucleotide codons to be grouped incorrectly
- 12. IV. RESULTS OF MUTATIONS • CHANGES TO DNA CAN INCREASE CHANCES OF GENETIC VARIATION THAT MAY OR MAY NOT BE HARMFUL 1. Hereditary disorders: inherited mutation a. _SICKLE CELL ANEMIA b. _PKU: phenylketonuria c. _CYSTIC FIBROSIS 2. Cancer: non-inherited mutation