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Thesunwashotbuttheo ldmandidnotgethishat. This is (kind of) like a strand of DNA. Each letter represents a base (A,C,T,G).

The sun was hot but the old man did not get his hat. It has meaning when we break it into groups of three. This happens with DNA, too. Each set of three is a “codon” that codes for a specific protein.

Sometimes, mistakes happen during DNA replication (copying). Lets look at 3 types of replication errors.

The sun was hot bun the old man did not get his hat. This “swap” changes one codon to code for something else. N was substituted for t 1. Substitution

The sun was hho tbu tth eol dma ndi dno tge thi sha t. Sometimes a new base pair is added. This throws everything after it off, making nonsense out of those codons. H was inserted 2. Insertion

The sun was hob utt heo ldm and idn otg eth ish at. Sometimes a base pair is deleted which also throws everything after it off. T was deleted 3. Deletion

Mr. Fix-it  Our bodies have strategies in place to deal with mistakes.  Most mutations cause no effect at all.  Some are serious, and might prevent the organism from ever being born.  Every once in a (great) while, a mutation will happen to improve an organism. We’ll learn more about this in our Evolution unit!

Think of a car…  Even if something like the side mirror breaks, you can still drive it.  If something more important malfunctions, like the brakes, you may have more difficulty.

 Some cause slight changes in phenotype

A few cause dangerous conditions such as sickle cell anemia.

Mutations (Follow Up)  Go to Mr. Hill’s Website, Unit 6: Genetics  Find Audio/Video (very bottom)  Open “Perfection is Skin Deep”  Read article  You can listen too IF you have earbuds.  Done?  Find Vocabulary Flash Cards (Quizlet) on Website and explore/practice.  Try “Scatter” or “Test”