MUTATIOMUTATIONS!NS!

Is this what we mean?Is this what we mean?

Is this what we mean?Is this what we mean?“Frog mutations are not typically very cute, and they’re often correlated quite directly to pollution. While frogs don’t seem to mind having a few extra limbs here or there, it’s more disturbing when one knows the source of their discomfort and strange formation.”

Source: http://webecoist.com/2010/09/23/yellow-lobsters-winged-cats-hulking-whippets-and-more/

Is this what we mean?Is this what we mean?“This large whippet is named Wendy and she has something called “double muscling”, causing her to have much higher muscle mass than her lithe counterparts. Included in these photos are a few typical whippets to use as comparison. Wendy is friendly and by all accounts, happy, but if there’s ever a hulk television show starring dogs… we know who to cast.”

Source: http://webecoist.com/2010/09/23/yellow-lobsters-winged-cats-hulking-whippets-and-more/

Is this what we mean?Is this what we mean?

Skin Pigmentation in Humans

This first video clip answers the question of why humans evolved different skin pigments: http://www.youtube.com/watch?v=-1b_li5oxNU

We mean it all! We mean it all! (Well, except the X-Men (Well, except the X-Men

part)part)So, are mutations good, So, are mutations good,

bad, neutral, or all of bad, neutral, or all of these?these?

Mutations!Mutations! Mutation: A natural process

that changes a DNA sequence. Can be good, bad, or neutral.

Rare all-black penguin mutation.

Mutations!Mutations!

Mutations make every individual unique.

They account for all the variation we see in human hair color, skin color, height, shape, and behavior.

OBSERVATION OBSERVATION #5:#5:

Individuals with Individuals with advantageousadvantageous

variations have a better variations have a better chance ofchance of

surviving than those with less surviving than those with less

advantageous variations.advantageous variations.

OBSERVATION #6OBSERVATION #6Survival allows Survival allows reproductionreproduction

When the surviving wormeaters When the surviving wormeaters reproduce what kind of beaks will reproduce what kind of beaks will their offspring most likely have?their offspring most likely have?

OBSERVATION #7:OBSERVATION #7:Many variations are inherited (in other words, offspring tend to resemble their parents).

What do you predict would happen What do you predict would happen to the to the ## of individuals with the of individuals with the

advantageous advantageous variation in the next variation in the next generation?generation?

INFERENCE #2:INFERENCE #2:The # of individuals with advantageous variations will increase in each new generation. The # with disadvantageous traits will decrease.

What about the # of individuals with the disadvantageousdisadvantageous variations?

Point Point MutationsMutations Point Mutation: The

substitution of a single nucleotide. Three kinds:1. Point missense –

causes one amino acid to change (can be good or bad; leads to variation)

Sickle Cell Anemia is caused by a point missense mutation.

Point Point MutationsMutations2.Point nonsense – inserts a

premature stop (usually bad)

Silent MutationsSilent Mutations

3. Silent mutation – the DNA has a substitution mutation, but still codes for the same amino acid as “normal” DNA.

In other words, the protein looks like no mutation is present, but the DNA tells otherwise.

Frameshift Mutation: Addition or deletion of a single nucleotide causes the codons to be incorrectly grouped.If this occurs near the beginning of a gene, it prevents many codons from coding for the proper amino acids.

Example of a point mutation…Example of a point mutation…Original: Original: The fat cat ate the wee rat.The fat cat ate the wee rat.

Point Mutation:Point Mutation: The fat The fat rrat ate the wee rat.at ate the wee rat.

Example of a frameshift Example of a frameshift mutation…mutation…Original: Original: The fat cat ate the wee The fat cat ate the wee

rat.rat.

Frameshift:Frameshift: The fat caThe fat caaa tet hew eer tet hew eer atat..

(the “t” was deleted (the “t” was deleted completely)completely)

Other drivers of Other drivers of mutationmutation Radiation,

chemicals, and UV radiation from the sun can damage thousands of nucleotides every day.

Our DNA can reverse mutations most of the time.

DNA RepairDNA Repair

Only when DNA changes are in egg and sperm cells are they passed on to the next generation.

Without mutation there would be no variation, and without variation there would be no evolution.