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4 Cards in this Set
- Front
- Back
What are 2 conditions of change that lead to variation?
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*must be heritable - affect germ line
*must not prevent the individual from reproducing |
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Describe the main sources of genetic variation.
*There are 6 listed in the notes. |
*Mutation within a gene - point mutations: change a single nucleotide, duplicate or delete one or more nucleotides in gene DNA sequence usually a result of rare “mistakes” made during DNA replication or failures in DNA repair after DNA damage.
*Gene duplication: existing gene, its part or large segment of DNA can be duplicated. It creates a set of closely related genes in a single cell. After additional mutations in cell progeny, duplicated genes can assume functions distinct from those of the original gene *source of genetic novelty for evolving organisms. *Gene deletion: Individual genes or blocks of genes can be lost through chromosome breakage and failures to repair. *Exon shuffling: two or more existing genes can be broken and rejoined to make a hybrid gene containing DNA segments from different genes. *Horizontal (intercellular) gene transfer: piece of DNA can be transferred from the genome of one cell to the genome of another cell or to the genome of another species. *Movement of transposable elements: cause of often observed “spontaneous” mutations, can create new exon arrangements - new genes. |
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Define: point mutation.
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A mutation that changes a single nucleotide.
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Define: conjugation.
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Process by which bacterial cells can horizontally transfer DNA.
-Plasmids often carry genes for antibiotic resistance and can be transferred from species to species. |