mutations!
DESCRIPTION
MUTATIONS!. Part One. MUTATIONS: WHAT ARE THEY ?. MUTATIONS:. are changes in the genetic material of the cell. can occur at the level of an individual DNA strand ( a point mutation ) or to an entire chromosome ( a chromosomal mutation ). MUTATIONS:. - PowerPoint PPT PresentationTRANSCRIPT
MUTATIONS!Part One
MUTATIONS: WHAT ARE THEY ?
MUTATIONS:
are changes in the genetic material of the cell.
can occur at the level of an individual DNA strand (a point mutation) or to an entire chromosome (a chromosomal mutation)
usually lead to a decrease, rather than an increase, of information.
A loss of information in the cell leads to a loss of some function.
MUTATIONS:
Information is lost….
Information is lost….
Information is lost….
Information is lost….
The loss of information means that most
mutations areeither harmful
or have no effect.
The loss of information means that most
mutations areeither harmful
or have no effect.
The loss of information means that most
mutations areeither harmful
or have no effect.
The loss of information means that most
mutations areeither harmful
or have no effect.
.
Now and then a mutation will offer a benefit to an organism.
.
However, the idea that a single mutation would lead
to a huge, dramatic change in a single generation
(like the X-Men characters) is just wrong.
TYPES OF MUTATIONS:
Point mutations are caused by random errors in the copying process (during transcription)
TYPES OF MUTATIONS:
Chromosomal mutations occur when chromosomes fail to properly separate during meiosis
ChromosomalMutations:
chromosome
supercoils
coils
nucleosome
histones
DNAdoublehelix
• changes in the number or structure of chromosomes
ChromosomalMutations:
• changes in the number or structure of chromosomes
• typically harmful in humans
ChromosomalMutations:
• can occur in four different ways: deletion, duplication, inversion
and translocation
ChromosomalMutations:
DELETION
ChromosomalMutations:
DELETION
DUPLICATION
ChromosomalMutations:
DELETION
DUPLICATION
INVERSION
ChromosomalMutations:
DELETION
DUPLICATION
INVERSION
TRANSLOCATION
ChromosomalMutations:
Non-Disjunction:• is the failure of the chromosomes to properly separate during meiosis
homologous chromosomesfail to separate
Meiosis I: non-disjunction
Meiosis II:
• leads to organisms with the wrong number of chromosomes
• causes birth defects like Down’s Syndrome (trisomy-21)
Non-Disjunction:
POINTMutations:
chromosome
supercoils
coils
nucleosome
histones
DNAdoublehelix
POINTMutations:
• are changes in single base pairs of DNA
• can lead to production of faulty (misshapen) proteins, or no protein at all
POINTMutations:
• often have no effect: UCC codes for serine, for example, but so does UCU, UCA or UCG
• that change the last letter in a DNA triplet may lead to the same amino acid
POINTMutations:
• that do this are called sense or silent mutations
POINTMutations:
• which lead to a different amino acid, however, are called missense mutations
• Depending on the amino acid, these can be good, bad or neutral
POINTMutations:
• which lead to a stop codon (UAA, UAG or UGA) are called nonsense mutations
• These lead to loss of function and are usually bad
POINTMutations:
• Sense, missense and nonsense mutations are typically caused by substitution of one nucleotide for another, changing the meaning of only one codon. • Deletion or insertion of an entire nucleotide leads to frameshift !
Frameshift Mutationsalter everything that follows:
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THE HOG ATE THE RAT MAN
THE DOG ATE HER ATM AN…
THE OGA TEH ERA TMA N…