1. Mutations
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2. SB2d
Describe the relationships between changes in DNA and potential appearance of new traits including:
Alterations during replication
Insertions
Deletions
Substitutions
Mutagenic factors that can alter DNA
High energy radiation (x-rays and ultraviolet)
Chemical
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3. Mutations
Mutations- are changes in the DNA sequence that affect genetic information
TYPES
Gene mutations- result from changes in a single gene
AKA Point Mutation (affects one nucleotide)
3 types: Substitution, Insertion, and Deletion
Chromosomal mutation- result from changes in whole chromosomes
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4. Gene mutations Substitution Mutations that affects only one base
Equivalent to changing one letter in a sentence, such as, changing the “c” in cat to an “h”
Original: The fat cat ate the wet rat.
Substitution: The fat hat ate the wet rat.
Mistakes are corrected by DNA polymerase if not, DNA is altered.
Results in one wrong amino acid
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5. Gene mutations Frameshift Mutations
Mutations in which one or more bases are inserted (insertion) or deleted (deletion)
Causes reading frame to shift
Equivalent to removing the 't' from cat is removed, while keeping the original letter spacing:
Original: The fat cat ate the wet rat.
Frame Shift: The fat caa tet hew etr at.
Frame Shift: The fat cat ate the wet rat a.
Results in codons that code for a different amino acid
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6. Gene mutations Insertions
Mutations that result in the addition of extra DNA. Insertions can also cause frameshift mutations, and generally result in a nonfunctional protein.
Equivalent to inserting xlw for the word ate
Original: The fat cat ate the wet rat.
Insertion: The fat cat xlw ate the wet rat.
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7. Chromosomal mutations
Deletion
Mutations that result in missing DNA. These can be small, such as the removal of just one "word," or longer deletions that affect a large number of genes on the chromosome. Deletions can also cause frameshift mutations.
Equivalent to deleting the word cat.
Original: The fat cat ate the wet rat.
Deletion: The fat ate the wet rat.
Results in a severely altered or nonfunctional protein
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8. Chromosomal mutations
Duplication
Mutation that produces an extra copy of all or part of a chromosome.
Usually no affect on the organism
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9. Chromosomal mutations
Inversion
Mutations in which an entire section of DNA is reversed. A small inversion may involve only a few bases within a gene, while longer inversions involve large regions of a chromosome containing several genes. Original: The fat cat ate the wet rat.
Insertion:The fat tar tew eht eta tac.
Results in DNA alterations
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10. Chromosomal mutations
Translocation
Mutations that occur when part of one chromosome breaks off and attaches to another, nonhomologous chromosome
Can affect gene function
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11. Body cell vs. Sex cell Mutations
Mutations in body cells do not affect offspring.
Affect only the organism in which they occur
Mutations in sex cells can be harmful or beneficial to offspring.
Source of genetic variation
Natural selection often removes mutant alleles from a population when they are less adaptive.
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12. Benefits/Causes of Mutations
Replication errors can cause mutations.
Mutagens, such as UV ray, X rays, gamma rays and chemicals, can cause mutations.
Some cancer drugs use mutagenic properties to kill cancer cells.
Beneficial:
Can produce proteins with new or altered functions that can be useful to organisms
Polyploid plants are larger and stronger than diploid plants.
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