Mutations

Front

Mutation Noun

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[myoo-tay-shun]

Back

Mutation

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A heritable change in the genetic information of an organism, altering the DNA sequence or chromosome structure.

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Example: This diagram shows that a change (mutation) in a gene's DNA sequence can cause the cell to produce a different, abnormal protein.

Front

Point Mutation Noun

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[point myoo-tay-shun]

Back

Point Mutation

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A gene mutation that involves a chemical change in a single base pair at a specific point in the DNA sequence.

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Example: This diagram shows a segment of a DNA sequence before and after a mutation. One letter (base 'A') is changed to another ('G'), illustrating a point mutation.

Front

Frameshift Mutation Noun

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[freym-shift myoo-tay-shun]

Back

Frameshift Mutation

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A mutation caused by nucleotide insertion or deletion, which shifts the 'reading frame' of the genetic message during translation.

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Example: This diagram uses a simple sentence to show how deleting one letter (a base) shifts the reading 'frame', causing all the following three-letter groups (codons) to change.

Front

Mutagen Noun

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[myoo-tuh-jen]

Back

Mutagen

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A chemical or physical agent in the environment that can interact with DNA and cause a permanent genetic mutation.

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Example: A mutagen, like UV radiation from the sun, is an agent that can damage DNA and cause a genetic mutation, such as a thymine dimer.

Front

Polyploidy Noun

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[pol-ee-ploi-dee]

Back

Polyploidy

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The condition in which an organism possesses one or more extra complete sets of chromosomes within its cells.

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Example: This diagram shows how polyploidy is a mutation where an organism has more than two sets of chromosomes, comparing haploid (n), diploid (2n), and polyploid (3n, 4n) states.

Front

Substitution Noun

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[sub-sti-too-shun]

Back

Substitution

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A type of point mutation in which one nitrogenous base in a DNA sequence is changed to a different base.

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Example: This diagram shows an original DNA sequence where one base (A) is swapped out for a different base (G) in the mutated sequence, illustrating a substitution mutation.

Front

Insertion Noun

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[in-sur-shun]

Back

Insertion

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A type of frameshift mutation in which one or more nucleotide base pairs are added into a DNA sequence.

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Example: This diagram shows an insertion mutation, where an extra nucleotide base (the highlighted 'C') is added into a DNA sequence, changing the original genetic code.

Front

Deletion Noun

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[dih-lee-shun]

Back

Deletion

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A mutation where one or more bases are removed from a DNA sequence, or the loss of a chromosome segment.

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Example: This image shows a part of a DNA sequence where one base (A) is removed, making the sequence shorter. This process is a deletion mutation.

Front

Silent Mutation Noun

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[sy-lent myoo-tay-shun]

Back

Silent Mutation

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A mutation that changes a single nucleotide but does not change the amino acid sequence of the resulting protein.

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Example: A change in the DNA code (from C to T) alters the messenger RNA, but because of redundancy in the genetic code, it still produces the exact same amino acid (Lysine), resulting in no change to the final protein.

Front

Missense Mutation Noun

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[mis-sens myoo-tay-shun]

Back

Missense Mutation

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A point mutation where a single nucleotide change results in a codon that codes for a different amino acid.

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Example: This image uses an analogy where changing one letter in a sentence (from 'cat' to 'rat') changes its meaning, similar to how a missense mutation changes a single DNA base, resulting in a different amino acid and protein.