Mutations are changes in DNA sequence that may occur naturally during DNA replication or be caused by mutagens. There are two types of mutations: somatic mutations, which occur in somatic cells and are not inherited, and germline mutations, which occur in gametes and are passed to offspring. Mutations can be caused by physical mutagens like radiation or chemical mutagens like mustard gas. Chromosomal mutations include deletions, inversions, translocations, duplications, and aneuploidy. Gene mutations include frameshift, substitution, insertion, and deletion mutations. Several databases track somatic mutations in cancer genomes, including COSMIC, ICGC, and TCGA.

1. MUTATIONS
BY: BAIJAYANTI MALA SAHOO
scholar no -182104107

3. CONTENTS
• 1. WHAT ARE MUTATIONS
• 2.CAUSE OF MUTATION
• 3. PHYSICAL AND CHEMICAL MUTAGENS
• 4.CHROMOSOMAL MUTATIONS AND IT’S TYPES
• 5. GENE MUTATION AND IT’S TYPES
• 6.REFERENCES

4. • Changes in the nucleotide sequence of DNA
• IT is of two types-
1.Somatic mutation
2. Germline mutation
• Somatic mutations occur in somatic cell and are not
passes to offspring
• Germline mutations occurs in gametes and are
passed to offspring

5. CAUSE OF MUTATION
•NATURAL CAUSE –
DNA fails to copy accurately
•MUTAGENS – It is an agent which causes mutation
1. PHYSICAL
2. CHEMICAL

6. PHYSICAL AND CHEMICAL MUTAGENS
• PHYSICAL MUTAGENS-
• 1. IONIZING RADIATIONS-
eg - alpha ray, beta ray, gamma ray
• 2 .NON IONIZING RADIATIONS-
eg – uv ray
• CHEMICAL MUTAGENS - Certain chemical like
dimethyl sulfonate, mustard gas, , caffeine, food
preservatives , pesticides also cause mutations

7. TYPES-
• SPONTANEOUS MUTATION-
They are mainly caused during DNA replication or incorporation of incorrect
nucleotide in the growing DNA chain.
they occur naturally during DNA replication
• INDUCED MUTATION -
These are caused by mutagens

8. CHROMOSE MUTATION

9. • Chromosome mutations may involve
1.changing the structure of a chromosome
2.the loss or gain of a part of a chromosome
TYPES-
1.deletion
2. inversion
3.translocation
4. duplication
5.aneuploidy
6. polyploidy

10. DELETION
• A piece of a chromosome is lost

11. INVERSION• Chromosome segment breaks off
• Segment flips around backwards
• Segment reattaches

12. DUPLICATION
Occurs when a gene sequence is repeated

13. TRANSLOCATION
Part of one chromosome is transferred to another chromosome

14. ANEUPLOIDY
• The abnormal condition where one or more chromosomes of a normal
set of chromosomes are missing or present in more than their usual
number of copies
• TYPES-
1.nullisomy
2.monosomy
3.trisomy
4. tetrasomy

15. NULLISOMY
• The loss of both the members of a homologous pair of chromosomes
• Represented as 2N-2
• Where N refers to the haploid no. of chromosomes
• So here we have 44 chromosomes
• eg - wheat

16. MONOSOMY
• The loss of single chromosome
• Represented as 2N-1=45
• Eg- turner syndrome

19. TRISOMY
• Gain of an extra copy of a chromosome
• Represented by 2N+1
• Eg- Edward syndrome

22. TETRASOMY
• The gain of an extra pair of homologous chromosomes
• represented by 2N+2
• eg- cat eye syndrome, tetrasomy18p

24. POLYPLOIDY
• The presence of more than 2 genomic sets of chromosomes
• Polyploides include triploid, tetraploid even higher no of
chromosomes
• Mostly found in plants . eg- potato, wheat

25. GENE MUTATION

26.  Changes in the nucleotide sequence of a gene
TYPES-
1. frameshift
2. substitution
3. insertion
4. deletion

27. FRAMESHIFT MUTATION
• Since protein-coding DNA is divided into codons
three bases long, insertions and deletions can alter
a gene so that its message is no longer correctly
parsed. These changes are called frameshifts

29. SUBSTITUTION
• A substitution is a mutation that exchanges one base for
another (i.e., a change in a single "chemical letter" such as
switching an A to a G). Such a substitution could :
• change a codon to one that encodes a different amino acid
and cause a small change in the protein produced.
• For example, sickle cell anemia is caused by a substitution in
the beta-hemoglobin gene, which alters a single amino acid in
the protein produced.
• change a codon to one that encodes the same amino acid
and causes no change in the protein produced. These are
called silent mutations.

32. INSERTION AND DELETION
• INSERTION-
insertion are mutations in which extra base pairs are inserted into DNA
• DELETION-
Deletions are mutations in which a section of DNA is lost or deleted.

34. BIOINFORMATIC DATABASES
• 1.COSMIC-(Catalogue Of Somatic Mutations In Cancer)
• One of the most comprehensive collections of somatic mutations.
• Contains information about mutations, genes and samples.
• Data can be accessed via an online search engines or downloaded
from the Sanger Institute ftp site.
• 2.ICGC-(International Cancer Genome Consortium)
• Provides a great overview of a long list of cancer related projects.
• Has some open access and also some controlled access data.

35. • 3. SM-EGFR-DB (Somatic Mutations in Epidermal Growth Factor Receptor
Data Base)
• Main focus is non-small cell lung cancer, but has information about other
cancer types.
• Contains information published in peer reviewed journals.
• 4. SomamiR DB (Somatic mutations impacting microRNA targeting)
• One of the more specialized databases concentrating on miRNA related
mutations.
• Database can be downloaded in the form of tab limited text files.
• 5. The Cancer Genome Atlas
• Collection of biological specimens from cancer patients.
• Specimens are analysed with different methods.
• Open access and controlled access datasets are available.

36. REFERENCES
• https://www.omicsonline.org/scholarly/gene-mutations-journals-
articles-ppts-list.php
• https://www.sciencedirect.com/journal/mutation-research-reviews-
in-mutation-research
• https://www.sciencedirect.com/journal/mutation-research-reviews-
in-mutation-research

37. THANK YOU