Introduction of mutation, types of mutation effects of mutation a brief description

1. By
Samina Husain

2. MUTATIOMUTATIO
NSNS

3. SYNOPSIS
 INtrOductION
 tYPeS Of mutatION
 chrOmOSOmal mutatION
 deletION
 INverSION
 traNSlOcatION
 NON dISjuNctION
 duPlIcatION
 GeNe mutatION
 POINt mutatION
 SubStItutION
 INSertION
 deletION
 frameShIft
 cONcluSION
 refereNceS

4. WHAT AREWHAT ARE
MUTATIONS?MUTATIONS?
 Mutation is the permanent alteration of the
nucleotide sequence of the genome of an organism, virus, or
extra chromosomal DNA or other genetic elements.
Mutations result from errors during DNA replication or
other types of damage to DNA.
 Changes in chromosome number may involve even larger
mutations, where segments of the DNA within chromosomes
break and then rearrange. For example, in the Homininae,
two chromosomes fused to produce human chromosome 2;
this fusion did not occur in the lineage of the other apes, and
they retain these separate chromosomes.
 Neutral mutation are defined as mutations whose effects do
not influence the fitness of an individual. These can
accumulate over time due to genetic drift

5. TYPES OF
MUTATIONS

6. CHROMOSOMAL
MUTATIONS
 Chromosomal mutation occur as a results of
structural Or numeric changes in the
chromosome of the organism.
A chromosome , abnormality, aberration,
or mutation is a missing, extra, or irregular
portion of chromosomal DNA.It can be from an
atypical number of chromosomes or a structural
abnormality in one or more chromosomes.
Chromosome mutation was formerly used in a
strict sense to mean a change in a chromosomal
segment, involving more than one gene.

7. CHROMOSOMAL
MUTATIONS
STRUCTURAL CHANGES
Five types exist:
Deletion
Inversion
Translocation
Nondisjunction
Duplication

8. DELETION
Deletion means to delete one or more
portion of chromosome .
For example ->
ABCDEFG ABEFG

9. INVERSION
Inversion occur when number of genes in a chromosome is
not changed but the sequence of genes is altered by the
rotation of the genes block within a chromosome by
180 degree.
ABCDEFG AEDCBFG (BCDE inverted.)

10. DUPLICATION
Duplication occur when some portion of
chromosome get repeated so that genes located on
the repeated portion are represented more that
once in that chromosome.
ABCDEFG ABCDCDEFG

11. TRANSLOCATION
Translocation occur when the block of
genes exchange between two non-
homologous chromosome.

12. NON
DISJUNCTION
 Failure of chromosomes to separate during
meiosis.
 Causes gamete to have too many or too few
chromosomes.
 Disorders:
 Down Syndrome – three 21st
chromosomes
 Turner Syndrome – single X chromosome
 Klinefelter’s Syndrome – XXY chromosomes

14. CHROMSOMAL MUTATION
NUMERICAL CHANGES
Three types:
Haploidy
Euploidy
 Monoploid
 Diploid
 Polyploid
Aneuploidy

16. GENE MUTATIONS
 Mutation occur due the changes in the chemistry
of genes that is Gene Mutation or Point Mutation.
 The gene so modified are the mutant genes. Genes
are made up of DNA segments , hence any changes
in the sequence of nitrogenous base of DNA
representing a particular gene called Gene
Mutation.
 A gene mutation is a permanent alteration in the
DNA sequence that makes up a gene, such that the
sequence differs from what is found . Mutations
range in size; they can affect anywhere from a
single DNA building block (base pair) to a large
segment of a chromosome that includes multiple
genes.

17.  Gene mutations can be classified in two major ways:
• Hereditary mutations are inherited from a parent and are present
throughout a person’s life in virtually every cell in the body. These
mutations are also called germ line mutations because they are present
in the parent’s egg or sperm cells, which are also called germ cells.
When an egg and a sperm cell unite, the resulting fertilized egg cell
receives DNA from both parents. If this DNA has a mutation, the child
that grows from the fertilized egg will have the mutation in each of his or
her cells.
• Acquired (or somatic) mutations occur at some time during a person’s
life and are present only in certain cells, not in every cell in the body.
These changes can be caused by environmental factors such as
ultraviolet radiation from the sun, or can occur if a mistake is made as
DNA copies itself during cell division. Acquired mutations in somatic
cells (cells other than sperm and egg cells) cannot be passed on to the
next generation.

18.  Genetic changes that are described as de novo (new)
mutations can be either hereditary or somatic. In some
cases, the mutation occurs in a person’s egg or sperm cell
but is not present in any of the person’s other cells. In other
cases, the mutation occurs in the fertilized egg shortly after
the egg and sperm cells unite. (It is often impossible to tell
exactly when a de novo mutation happened.) As the
fertilized egg divides, each resulting cell in the growing
embryo will have the mutation. De novo mutations may
explain genetic disorders in which an affected child has a
mutation in every cell in the body but the parents do not,
and there is no family history of the disorder.

19. TYPES OF GENE
MUTATIONS
Substitutions
 Transition
 Transversion
Frameshift
 Deletion
 Insertion

20. SUBSTITUTION MUTATION
 The nitrogenous vases substituted by another one.
 In this mutation only that codon is changed with
substituted base.so only one amino acid represented by
codon is replaced by another amino acid in the protein.
 It is of two types:
1. Transition:
In this substitution mutation a PURINE
nitrogenous base is replaced by another PURINE base &
similarly a PYRIMIDINE base is replaced by another
PYRIMIDINE base.

21. 2. Transversion:
In this substitution mutation a PURINE
nitrogenous base is replaced by PYRIMIDINE nitrogenous
base. OR PYRIMIDINE base is replaced by PURINE
base.

22. FRAMESHIFT
MUTATION
 It is the result of the insertion and deletion of DNA
segments representing the genes. Due the addition and
removal of base sequence, all the triplet codons down
stream od the insertion and deletion point are changed.
 Thus all the amino acid are coded by such changed codon
are different from the original ones in the proteins.
 In this way the frameshift mutation different from
substitution mutation.

23.  It is of two types:
1.Deletion mutation:
In this base is removed from the DNA base
sequence.
2.Insertion mutation:
in this the additional base is inserted in
the existing DNA base sequence.

24. AMINO ACID
SEQUENCE CHANGED

25. CAUSES OF MUTATION
 Spontaneous mutation:
some mutation seems to be due to the
mistake in base pairing during DNA replication.
 Mutagen:
chemical or physical agents in the
environment that cause mutation.
 Chemical mutagens: 5-boromouracil,2-
aminopurine,nitrous acid, hydroxylamine etc.
 Physical mutagens: x-ray, B-ray, gamma ray, ultravoilet
ray etc.

26. MUTATION
 Changes in DNA caused by mutation can cause errors in protein
sequence, creating partially or completely non-functional proteins.
Each cell, in order to function correctly, depends on thousands of
proteins to function in the right places at the right times.
 When a mutation alters a protein that plays a critical role in the body,
a medical condition can result. A condition caused by mutations in one
or more genes is called a Sheik disorder.
 Some mutations alter a gene's DNA base sequence but do not change
the function of the protein made by the gene. One study on the
comparison of genes between different species of Drosophila suggests
that if a mutation does change a protein, this will probably be harmful.

27. MUTATION CAN BE
BENEFICIAL!!!!
 Although mutations that cause changes in protein
sequences can be harmful to an organism, on occasions the
effect may be positive in a given environment. In this case,
the mutation may enable the mutant organism to
withstand particular environmental stresses better than
wild-type organisms, or reproduce more quickly. In these
cases a mutation will tend to become more common in a
population through natural selection.

28. CONCLUSION
 Mutation is the permanent alteration of
the nucleotides sequence of the genome of an organism
,virus , or extrachromosomal DNA or other genetic
elements. Mutations result from errors during DNA
replication or other types of damage to DNA.
 Mutations play a part in both normal and abnormal
biological processes including :evolution , cancer, and the
development of the immune system, including junctional
diversity.