extra-chromosomal-inheritance[1].pptx.pdfpdf

Slide 1: Title Slide
Extrachromosomal Inheritance

Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.

1. Presented By:
Dr SumeetKaur

2. INTRODUCTION
TYPES
MATERNAL INHERITANCE
ORGANELLAR INHERITANCE
INHERITANCE INVOLVING INFECTIOUS
PARTICLES
EVOLUTIONARY SIGNIFICANCE OF
ORGANELLES
SIGNIFANCE OF EXTRANUCLEAR
INHERITANCE

3. INTRODUCTION
Extra chromosomal inheritance defined as non-
mendelianinheritance, usually involving DNA in
replicating mitochondria and some other organelles of
cell.
Commonly defined as transmission through cytoplasm
rather than nucleus.
Inheritance due to genes located in cytoplasm (plasma
genes)
Plasma genes are located in DNA present in
mitochondria and in chloroplast.
Together both the DNAs are called organelle DNA.

4. EXTRANUCLEAR INHERITANCE IS
OF THREE TYPES :
Maternal inheritance
Organellarinheritance
Inheritance involving infectious
particles

5. MATERNALINHERITANCE
character of only one of the two parents is
transmitted to the progeny .
In most animals, parental mitochondria
enter the oocytecytoplasm after fertilization
their mt.dna is never transmitted to the
offspring.

6. Two types of coiling pattern
EXAMPLE :SHELL COILING IN
SNAIL(Lymneaperegra)
Right handed
Left handed (sinistralor
anticlockwise)
(Dextral or
clockwise)
Dextral coiling female Dextral coiling male
DD dd
All dextral
DD Dd
Dd dd
D d
D
d
Phenotypic ratio 3:1

7. IN RECIPROCAL CROSS:
Sinistralcoilingfemale Dextral coiling male
First generation : all sinisteraltype
Other generation: 3 sinistral: 1 dextral

8. ORGANELLAR INHERITANCE
CHLOROPLAST
MITOCHONDRIA

9. CHLOROPLAST INHERITANCE
Specialized organelle found in higher plants.
Two membranes: outer and inner membrane.
It possess internal membrane in the form of flattened
sacs known as thyllakoids.
They form stalk of disc at some places known as grana.
Chloroplast has three parts:
Envelope
Matrix
thyllakoids

11. Photosynthesis
Oxygen supply
Starch storage
Utilize carbondioxide
Synthesis of organic acid
Change into chromoplast
Food supply

12. GENOMIC STRUCTURE OF CHLOROPLAST DNA
it resemble large bacterial plasmid or
small chromosomes.
cpDNAis closed circular dsmolecule.
For exampleinMAIZE there are about 50
copies of DNA per chloroplast.
Single chloroplast contain information of
126 different protein molecule.
The complete sequence of cpDNAfound
in liverworts and tobacco.

13. Examples of cpDNA
IN Mirabilis jalapa
(a) female branch ×male branch
(green) (variegated)
Green plants only
(b) female branch ×male branch
(variegated) (green)
Variegated plants only

14. DISTINGUISHING FEATURES OF CHLOROPLAST
AND NUCLEAR DNA
cpDNAis circular while nuclear DNA is linear.
Histoneand other proteins are complexedwith
nuclear DNA but not with cpDNA.
After denaturationcpDNAreassociatemuch more
rapidly than nuclear DNA.
cpDNAis smaller in size than nuclear DNA.
Formation of D loop.

15. STRUCTURE OF MITOCHONDRIA
Powerhouse of the cell.
Position depends upon the
requirement of energy and
amino acid.
it consist of three parts:
oouter and inner membrane
oCristae
omatrix

16. FUNCTIONS OF MITOCHONDRIA
Store and release calcium .
Main seat of cell respiration.
Synthesis of amino acid(glutamicand aspartic acid).
Take part in maternal inheritance.
Synthesis of several biochemicalslike chlorophyll,
cytochrome, alkaloid.

17. GENOMIC CHARACTER OF MITOCHONDRIAL DNA
Mt.DNA is small genome
it contain their own DNA which may be circular or
linear.
Haploid in nature
Mt.DNA contain 37 genes and enclosed two types of
rRNAand 22tRNA.
G+C content of mt.DNA show variation from one sp. to
another.
example: 18% in yeast,47%inhigher plants.
Two region: coding region and central region .

19. MATERNAL INHERITANCE OF MITOCHONDRIAL DNA
During fertilization, sperm
only contribute its nucleus .
mitochondria of the sperm
cell are located at the
mitochondrial sheath which is
destroyed upon fertilization.
Only available mt.DNA is that
of the mother.

20. MITOCHONDRIA IN HUMAN
DISEASE
1.Laber’sherediataryoptic nuropathy(LHON)
Sudden onset of blindness in adult which is
associated with death of optic nerve due to mutation
in any of several mt.DNA.
Net effect of these mutation has reductive efficiency
of oxidative phosphorylationto such extent that the
function of optic nerve is destroy which result in
total blindness.
LHON show only maternal transmission.

21. 2. Pearson marrow-pancreas syndrome(PMPS)
It is also caused by mt.DNA in this disease there is loss
of bone marrow cell and this is fatal.
Parents of person affected by the syndrome are almost
normal. i.e. that mutation (deletion) in mt.DNA
occurs either during oogenesisor during the
development of fet0us.

22. DISTINGUISHING FEATURES OF
NUCLEAR DNA AND Mt.DNA
NUCLEAR DNA MITOCHONDRIAL DNA
Found in nuclear of cell.
Bounded by nuclear
envelope.
Two sets of 23 chromosome.
Maternal and paternal
inheritance.
Double helix.
DNA packed into chromatin.
Found in mt. of cell.
No nuclear envelope.
Several copies of the single
mt. DNA.
Maternal inheritance only.
Circular.
Not packed in chromatin.

23. CYTOPLASMIC MALE STERILITY
Progeny from cytoplasmicmale sterility and a
normal male fertile strain and are all male sterile.
it show cytoplasmicinheritance.
As a result CMS strain has to be pollinated by male
fertile strain in every generation for its
maintainence.
CMS is used in hybrid seed production in crops
like maize, jawar,bajraetc.

24. EVOLUTIONARY SIGNIFICANCE OF
ORGANELLES
The mitochondria and chloroplast once free
living bacteria that form symbiotic
relationships with the primitive eukaryotic
cell more than one billion years agois
referred as endosymbiotictheory.

25. INHERITANCE INVOLVING
INFECTIOUS PARTICLE
Non mendelianinheritance is associated with
infective particles like parasite, viruses.
EXAMPLE: kappa particles in paramecium.
T.M. sonneborndescribed the inheritance in
paramecium aurelia.
Thereare two strains of paramecium : killer and
sensitive.
Killer strain produce a toxic substance called
paramecinthat is lethal to other individual called
sensitive.

27. SIGNIFICANCE OF EXTRANUCLEAR
INHERITANCE
Role of various cytoplasmicorganelles in different
organism.
Mapping of chloroplast and mitochondrial in several
species viz. yeasts, maize, human etc.
Easily transfer to agronomic bases for their use in
development of superior hybrids.
Role of mitochondria in the menifestationof hetrosis.
It leads to generation of new variants (ornamental
plant).