Polyploidy, Mutation and Hybridization with reference to Medicinal Plants

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1. Polyploidy, mutation and hybridization with reference to medicinal plants DR. SIDDHI UPADHYAY H.O.D. & ASSOCIATE PROFESSOR Dept. of Pharmacognosy and Phytochemistry SIGMA INSTITUTE OF PHARMACY

2. Content Polyploidy with reference to medicinal plants Mutation with reference to medicinal plants Hybridization with reference to medicinal plants

3. Polyploidy with reference to medicinal plants

4. What is polyploids ? Polyploids are organisms with multiple sets of chromosomes in excess of the diploid number . Polyploidy is common in nature and provides a major mechanism for adaptation and speciation . Approximately 50-70% of angiosperms, which include many crop plants, have undergone polyploidy during their evolutionary process.

5. Classification of polyploids based on their chromosomal composition euploids aneuploids . Euploids constitute the majority of polyploids.

6. Euploidy are polyploids with multiples of the complete set of chromosomes specific to a species. Depending on the composition of the genome, euploids can be further classified into a u t opoly p loids allopolyploids .

7. Au t opolyploidy C ontaining of multiple copies of the basic set (x) of chromosomes of the same genome . •

8. occurs in nature through union of unreduced gametes. Natural autoploids include tetraploid crops such as alfafa, peanut, potato and coffee and triploid bananas .

9. Allopolyploidy A combination of genomes from different species .

10. They result from hybridization of two or more genomes followed by chromosome doubling or by the fusion of unreduced gametes between species . This mechanism is called non-disjunction . These meiotic aberrances result in plants with reduced vigor. Economically important natural alloploid crops include strawberry, wheat , oat , upland cotton , oilseed rape , blueberry and mustard .

11. Aneup l oidy are polyploids that contain either an addition or subtraction of one or more specific chromosome(s ) to the total number of chromosomes that usually make up the ploidy of a species. •

12. Aneuploids result from the formation of univalents and multivalents during meiosis of euploids . With no mechanism of dividing univalents equally among daughter cells during anaphase I, some cells inherit more genetic material than others . Similarly, multivalents such as homologous chromosomes may fail to separate during meiosis leading to unequal migration of chromosomes to opposite poles .

13. Examples for polyploids

14. How polyploids occur?

15. Inducing polyploids………… They occur spontaneously through the process of chromosome doubling. Spontaneous chromosome doubling in ornamentals and forage grasses has led to increased vigour. Examples tulip forage grasses ryegrasses have yielded superior varieties following spontaneous chromosome doubling .

16. breeders have harnessed the process of chromosome doubling in vitro through induced polyploidy to produce superior crops. For example, induced autotetraploids in the watermelon crop are used for the production of seedless triploid hybrids fruits . Such polyploids are induced through the treatment of diploids with mitotic inhibitors such as dinitroaniles and colchicine .

17. It is necessary to eliminate duplicated genes in a newly formed polyploid to avoid gene silencing as well as to stabilize fertility The increase in nuclear ploidy affects the structural and anatomical characteristics of the plant . Polyploidy results in increased leaf and flower size , stomatal density, cell size and chloroplast count

18. Hybrid vigor resulting from interspecific crosses in allopolyploids is one of the most exploited advantages of polyploid in plant breeding. A comparison between the leaf and flower of a (A) diploid and (B) induced tetraploid watermelon A B

19. mutation with reference to medicinal plants

20. Introduction Sudden heritable change in genetic material or character of an organism is known as mutation Individuals showing these changes are known as mutants An individual showing an altered phenotype due to mutation are known as variant Factor or agents causing mutation are known as mutagens Mutation which causes changes in base sequence of a gene are known as gene mutation or point mutation

21. Hi s tory English farmer Seth Wright recorded case of mutation first time in 1791 in male lamb with unusual short legs The term mutation is coined by Hugo de Vries in 1900 by his observation in Oenothera Sys t e m a t ic stu d y o f m uta t i o n was st a r t ed i n 1910 w h e n Mo r g an genetically analyzed white eye mutant of Drosophila H. J. Muller induced mutation in Drosophila by using X- rays in 1927 ; he was awarded with Nobel prize in 1946

22. Characteristics of Mutation Generally mutant alleles are recessive to their wild type or normal alleles Most mutations have harmful effect, but some mutations are beneficial Spontaneous mutations occurs at very low rate Some genes shows high rate of mutation such genes are called as mutable gene Highly mutable sites within a gene are known as hot spots. Mutation can occur in any tissue/cell (somatic or germinal) of an organism

23. Classification of mutation Based on the survival of an individual Lethal mutation – when mutation causes death of all individuals undergoing mutation are known as lethal Sub lethal mutation - causes death of 90% individuals Sub vital mutation – such mutation kills less than 90% individuals Vital mutation -when mutation don’t affect the survival of an individual are known as vital Supervital mutation – This kind of mutation enhances the survival of individual

24. Based on causes of mutation Spontaneous mutation- Spontaneous mutation occurs naturally without any cause. The rate of spontaneous mutation is very slow eg- Methylation followed by deamination of cytosine. Rate of spontaneous mutation is higher in eukaryotes than prokaryotes. Eg. UV light of sunlight causing mutation in bacteria Induced Mutation- Mutations produced due to treatment with either a chemical or physical agent are called induced mutation . The agents capable of inducing such mutations are known as mutagen. use of induced mutation for crop improvement program is known as mutation breeding. Eg. X- rays causing mutation in cereals

25. Based on tissue of origin Somatic mutation- A mutation occurring in somatic cell is called somatic mutation. In as e xua l ly r e pr o d u c i n g s pecies s o m a t ic m utat i ons t r a ns m i t s progeny to the next progeny Germinal Mutation- f r o m one When mutation occur in gametic cells or reproductive cells are known as germinal mutation. In sexually reproductive species only germinal mutation are transmitted to the next generation

26. Based on direction of mutation Forward mutation - When mutation occurs from the normal/wild type allele to mutant allele are known as forward mutation Reverse mutation- When mutation occurs in reverse direction that is from mutant allele to the normal/wild type allele are known as reverse mutation

27. Type of trait affected 1. Visible mutation- a f fects on phenotyp i c ch a rac t er T hose m utation and can be which d etec t ed by n o r m al observation are known as visible mutation 2. Biochemical mutation- mutation which affect the production of biochemicals and which does not not show any phenotypic character are known as biochemical mutation

28. Chromosome Mutations May Involve: – Changing the structure loss or gain

29. Chromosome Mutations Five types exist: – Deletion – Inversion – Translocation – Nondisjunction – Duplication

30. Deletion Due to breakage A piece of a chromosome is lost

31. Inversion Chromosome segment breaks off Segment flips around backwards Segment reattaches

32. Dupli c a tion Occurs when a gene sequence is repeated

33. Translocation Involves two chromosomes that aren’t homologous Part of one chromosome is transferred to another chromosomes

34. Translocation

35. Nondisjunction Failure of chromosomes to separate during meiosis Causes g amete t o h ave to o m a ny or too few chromosomes Disorders: Down Syndrome – Turner Syndrome – Klinefelter’s Syndrome –

36. Chromosome Mutation Animation

37. Types of Gene Mutations Include: – Point Mutations – Substitutions – Insertions – Deletions – Frameshift

38. Point Mutation Change of a single nucleotide Includes the deletion, insertion, or substitution of ONE nucleotide in a gene

39. Point Mutation Sickle Cell disease is the result of one nucleotide substitution Occurs in the hemoglobin gene

40. Frameshift Mutation Inserting or deleting one or more nucleotides Changes the “ reading frame ” like changing a sentence Proteins built incorrectly

41. Gene Mutation Animation

42. hybridization with reference to medicinal plants

43. MEANING OF HYBRIDIZATION  Individual produced as a result of cross between two genetically different parents is known as hybrid. The natural or artificial process that results in the formation of hybrid is known as hybridization.  The production of a hybrid by crossing two individuals of unlike genetical constitution is known as hybridization. Hybridization is an important method of combining characters of different plants. Hybridization does not change genetic contents of organisms but it produces new combination of genes.

44. OBJECTIVES OF HYBRIDIZATION 1 . T o a r ti f icial l y c r eate a v ariable population for the selection of types with desired combination of characters. To combine the desired characters into a single individual. To exploit and utilize the hybrid varieties .

45. TYPES OF HYBRIDISATION Basing on the taxonomic relationship of two parents, Hybridisation grouped into 2 types HYBRIDISATION I N TE R V AR I E T AL HY BRID I S A TION DISTANT HY BRID I S A TION I N TRAS P ECI F IC I N TERSP ECIF IC INTRA GENERIC INTER GENERIC

46. TYPES OF HYBRIDIZATION :  (i) Intra-varietal hybridization:  The crosses are made between the plants of the same variety.  ii) Inter-varietal or Intraspecific hybridization:  The crosses are made between the plants belonging to two different varieties.  (iii) Interspecific hybridization or intragenric hybridization:  The crosses are made between two different species of the same genus.

47. Procedure of Hybridization: It involves the following steps: Selection of parents. Selfing of parents or artificial self-pollinat Emasculation. Bagging Tagging Crossing Harvesting and storing the F, seeds Raising the F 1 generation.

48. Emasculation Bagging

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