Contents - Definition of cytoplasmic inheritance Mendelian inheritance , Non Mendelian inheritance, difference between Mendelian and non Mendelian inheritance, maternal effect - shell coiling , inheritance due to infective particle- kappa particle in paramecium

2. DEFINITION:
•WHEN THE TRANSMISSION OF TRAITS/ CHARACTERS FROM PARENTS TO OFFSPRING IS
GOVERNED BY CYTOPLASMIC GENES , IT IS KNOWN AS CYTOPLASMIC INHERITANCE.
•INHERITANCE DUE TO GENES LOCATED IN CYTOPLASM IS CALLED CYTOPLASMIC
INHERITANCE.
•GENES GOVERNING THE TRAITS SHOWING CYTOPLASMIC INHERITANCE ARE LOCATED
OUTSIDE THE NUCLEUS & IN THE CYTOPLASM , IT IS KNOWN AS PLASMA GENES.
•PLASMA GENES= CP DNA / MT DNA

3. MENDELIAN INHERITANCE :
• THERE IS CONTRIBUTION OF BOTH MALE & FEMALE PARENTS , SO THE RECIPROCAL CROSSES ARE
IDENTICAL .
• THE SEGREGATION PRODUCES 3:1 RATIO IN F1 MONOHYBRID & 9:3:3:1 RATIO IN F2 DIHYBRID CROSSES,
THEREFORE IT IS DISTINCT.
• THE GENE SHOWING THE MENDELIAN INHERITANCE ARE LOCATED ON CHROMOSOME OF NUCLEI ,
THEREFORE KNOWN AS NUCLEAR GENE.
• MATERNAL EFFECTS – NOT OBSERVED
• GENE MAPPING IS EASY

4. NON MENDELIAN INHERITANCE :
• THE CYTOPLASM IS USUALLY CONTRIBUTED ENTIRELY BY ONE PARENT (USUALLY FEMALE PARENT)
• SO THE RECIPROCAL CROSSES GIVE DIFFERENT RESULTS.
• THE GENE SHOWING NON MENDELIAN INHERITANCE ARE LOCATED IN DNA PRESENT IN MITOCHONDRIA
(MT. DNA) & IN CHLOROPLASTS (CP. DNA).
• THEREFORE GENE MAPPING IS DIFFICULT.

5. DIFFERENCES B/W MENDELIAN &
CYTOPLASMIC INHERITANCE
Particulars Mendelian inheritance Cytoplasmic
inheritance
Governed By NUCLEAR GENES PLASMA GENES
Segregation Pattern DISTINCT NOT DISTINCT
Reciprocal
Diifferences
NOT OBSERVED OBSERVED
Maternal effects NOT OBSERVED OBSERVED
Gene mapping EASY DIFFICULT
Location of genes CHROMOSOMES OF
NUCLEI
CHLOROPLAST &
MITOCHONDRIA

6. TYPES OF CYTOPLASMIC INHERITANCE
THERE ARE THREE TYPES OF CYTOPLASMIC INHERITANCE :
1. MATERNAL EFFECT
2. INHERITANCE DUE TO INFECTIVE PARTICLES
3. CYTOPLASMIC INHERITANCE

7. MATERNAL EFFECTS
SHELL COILING IN SNAIL
• THIS WAS STUDIED BY - STURTEVANT
• HE SHOWED THAT THERE ARE TWO STRAINS OF WATER SNAILS THAT DIFFER EACH OTHER IN DIRECTION
OF COILING OF SHELL.
• IN ONE STRAIN , SHELL ALWAYS COILS TO THE LEFT(SINISTRAL)
• OTHER STRAIN, SHELL ALWAYS COILS TO THE RIGHT (DEXTRAL)

8. FROM STURTEVANT EXPERIMENT
• CASE 1 : WHEN DEXTRAL 🚺 CROSSED WITH SINISTRAL 🚹
ALL THE PROGENY HAVE DEXTRAL COIL IMPLYING THAT DEXTAL IS DOMINANT OVER SINSTRAL.
WHEN IT IS SELFED B/W F1 PROGENY – ALL THE F1 SNAILS WERE DEXTRAL

9. • CASE 2 : RECIPROCAL CROSS, IN THIS CASE SINISTRAL 🚺 AND DEXTRAL 🚹 WERE CROSSED
RESULT: PRODUCES F1 PROGENY THAT ARE ALL SINISTRAL.
IN THIS CASE ALSO AFTER SELFING OF F1 GENERATION , IT IS ONLY DEXTRAL COILED.

10. CONCLUSION:
• FROM THESE EXPERIMENT IT BECOMES CLEAR THAT COILING OF SNAILS IS NOT DETERMINED BY
INDIVIDUAL’S OWN GENE BUT BY THOSE OF MOTHER.
• THERE IS NO SEGREGATION WHEN F2 MALES ARE CROSSED WITH DEXTRAL FEMALES . ALL THEIR
PROGENY ARE DEXTRAL.
• NOW IT IS CLEAR THAT THE PATERNAL GENOTYPE IS NOT CRUICIAL IN DETERMINING THE PHENOTYPE OF
THE OFFSPRING.

11. KAPPA PARTICLES IN PARAMECIUM
• IT WAS STUDIED IN THE STRAIN OF PARAMECIUM AURELIA BY THE SCIENTIST SONNEBORNIN
THE YEAR 1938.
• PARAMECIUM AURELIA GIVES TWO TYPES OF STRAINS NAMELY KILLER STRAIN AND SENSITIVE STRAIN.
• THE KILLER STRAIN SHOULD HAVE DOMINANT GENE PLUS KAPPA PARTICLES.
• THE SENSITIVE STRAIN CONTAINS ANYONE FROM THE TWO ELEMENTS I.E. EITHER DOMINANT GENE OR
KAPPA PARTICLES.

12. WHAT IS KAPPA PARTICLES
• KAPPA ORGANISMS ALSO CALLED KAPPA PARTICLES , ARE GRAM NEGATIVE BACTERIUM FOUND IN
CERTAIN STRAINS OF THE PROTOZOAN PARAMECIUM AURELIA.
THESE BACTERIA WHEN RELEASED IN THE SURROUNDINGS , CHANGE TO P PARTICLES THAT SECRETE A
POISON[PARAMYECIN].
• THE KAPPA BEARERS, CALLED KILLERS ,ARE IMMUNE TO THE POISON THAT THEY ULTIMATELY UNLEASH.
• THE SENSITIVE STRAINS OF P.AURELIA ARE KILLED BY PARAMYECIN.

13. CONJUGATION IN PARAMECIUM
• IN PARAMECIUM WE KNOW THAT SEXUAL REPRODUCTION IS NOT VERY WELL DEVELOPED,THERE IS A
PRIMITIVE TYPE OF SEXUAL REPRODUCTION SHOWN WHICH IS KNOWN AS CONJUGATION.
• NOW WHEN TWO PARAMECIUM ARE MADE TO CONJUGATE AND CONJUGATION TAKES PLACE BETWEEN
THE KILLER STRAIN AND THE SENSITIVE STRAIN IT IS DONE IN LABORATORY.
• CONJUGATION IN NATURAL CONDITIONS IS NOT POSSIBLE SINCE THE KILLER STRAIN WILL PRODUCE
PARAMYECIN WHICH WILL KILL THE SENSITIVE STRAIN.
• SO IT IS CARRIED OUT IN LAB IN A CONDITION WHERE THE BOTTLE IN WHICH PARAMECIUM ARE KEPT IS
FREE OF PARAMYECIN.

14. CONT………………
• IF THE KILLER[KK] AND SENSITIVE[KK] STRAINS ARE ALLOWED TO CONJUGATE ALL THE
EXCONJUGANTS[THE CELLS SEPARATING AFTER CONJUGATION]WILL HAVE GENOTYPE[KK].
• PHENOTYPE OF THESE EXCONJUGANTS WILL HOWEVER, DEPEND UPON , DURATION FOR WHICH
CONJUGATION IS ALLOWED.

15. IF THE CONJUGATION IS NORMAL I.E. LASTS ONLY FOR LESS THAN 3
MINUTES THEN IN THAT CASE IT IS ONLY THE NUCLEAR MATERIAL
WHICH IS EXCHANGED.NO EXCHANGE OF CYTOPLASM TAKES PLACE
BETWEEN THE TWO ,BOTH KILLER AND SENSITIVE STRAINS ARE
PRODUCED.
.

16. HOWEVER, RARE OR PROLONG
CONJUGATION TAKES PLACE I.E. MORE THAN
3 MINUTES PERMITS MIXING OF
CYTOPLASM OF BOTH THE CONJUGANTS
AND RESULTS INTO KILLER STRAINS ONLY

17. THANK YOU !!