Extranuclear inheritance

Extranuclear inheritance

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Extranuclear Inheritance
S.KEERTHANAN
BS-1121

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What is Extranuclear inheritance?
•Extranuclear genes are found in cellular
organelles out of nucleus such as
mitochondria and chloroplasts.
•Via the Extranuclear genes, the characters
are inherited to next generation.
•It is known as cytoplasmic inheritance or
extrachromosomal inheritance.

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How was cytoplasmic inheritance discovered?
C. CORRENS (1909) and E.
BAUR (1909, 1910) described
crossings, for which the Mendelian
laws did not apply.

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C. CORRENS experiment…

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•Two types of pollen(white and green pollen) that
were used to fertilize the flowers:
•Branches with white leaves gave only white leaf
progeny.
•Branches with green leaves gave only green
progeny.
•Branches with variegated leaves gave green, white
and variegated progeny.

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conclusion
•Phenotype does not depend on
nuclear genotype (pollen not
involved)
•Must be dependent on cytoplasm
of female organs in the flower.
•Cytoplasmic inheritance.

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Leaf variegation
Caused by segregation of different types of chloroplasts

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Types of Extranuclear inheritance.
•Maternal inheritance : The cytoplasmic
organelles such mitochondria &
chloroplast are inherited with the egg
cytoplasm from the maternal parent.
Examples....
•Shell coiling in snail.
•Variegation in leaves of 4 o’ clock plant.

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Shell coiling in snail.

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Types of Extranuclear inheritance.

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Thank you…
The End