What are extra chromosomal inheritance ? Explain with an example .

Explanation

Extra chromosmal inheritance is the transmission of genes that occur outside the nucleus , It is found as inheritance occur through cytoplasmic organelles such as mitochondria and chloroplast. Evidence of extra chromosome inheritance was first reported by Correns in Mirabilis jalapa .
In 4 O . clock plant the variegative variety has some branches which carry normal green leaves, some branches with variegated leaves and some branches which have al white leaves.
Correns discovered that seed produced by flowers carried on the green branche gave gropeny which were all normal green . It made no difference whether the phenotype of the brance which carried the flower used for pollen was green , regardless of the pollen donor phenotype . these died in the seeding stage.Seeds from flowers on variegated branches gave three kinds of progeny green white and variegatived in varying proprtaions again regardlles of pollen donor phenotype . In other words the female parent and male made no contribution at all to the character . this effect is seen quite clearly in :