What is a mutation??? GENETIC MUTATIONS - PowerPoint Presentation

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What is a mutation???

GENETIC MUTATIONS

MISTAKES IN DNA

A MISTAKE CAN BE:

1. A point mutation – substitution, addition, or removal of a single DNA base.

2. A

frameshift

mutation –

a point mutation due to an addition

or deletion of a DNA base that causes a major change in the genetic code.

Sickle cell anemia is caused by a point mutation - substitution

Val-his-

leu

-

thr

-pro-

glu

-

glu

Val-his-

leu

-

thr

-pro-

val

-

glu

-

Muscular Dystrophy is caused by a

frameshift

mutation

THE CAT SAW THE DOG

CHANGE THE

W

TO A T:

THE CAT SA

T

THE DOG

CHANGE THE

D

TO AN

H

THE CAT SAW THE

H

OG

MAJOR MISSENSE: REMOVE THE “C”

THE ATS AWT HED OG

This type of mutation causes a protein to be non-functional. It is a severe problem and can be lethal.

MAJOR MISSENCE:

INSERT AN “

M

” after the first “The”.

THE

M

CA TSA WTH EDO G

The body cannot make sense out of the incorrect protein, just as the sentence no longer makes sense to you.

Nonsense

When a point mutation codes for a STOP in the middle of a sequence. Could be due to any of the point mutations.

Nonfunctional

dystrophin

, the protein that helps attach your skeletal muscle to its surroundings.

Some mutations involve whole chromosomes:

1. Deletion: A piece of a

chromosome is lost because of breakage during cell division

Cri du chat

Inversion: A piece of a chromosome breaks off and reattaches

backwards. The

effect

can be

lethal.

Duplication: A portion of the chromosome is copied and placed in the same chromosome.

Translocation: a piece of a chromosomes breaks off and reattaches to a non-homologous chromosome

Non-disjunction: A chromosome fails to separate from its homologue during meiosis

Turner’s Syndrome:

Klinefelter’s

Syndrome:

Mutations in nature: