1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India 1

2. OC-SB083-CP1-02 Introduction Programmes and Courses  SEP – SBT083–Unit 01 2

3. School of Science and Technology, Online Counseling Resource… Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) ‏ Experience: 11 Years arunmesh@hotmail.com 3

4. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam. 4

5. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Describe Mendel's laws of classical genetics. Describe experiments proving the principles of Mendel. 5

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction - 1  Mendel put forth the law of genetic inheritance.  He carried out the numerous experiments involving various crosses among the pea plants in 1856.  Mendel carried out mathematical and statistical analysis to derive these laws of inheritance.  At that time no one from the scientific community understand the importance of his research, therefore nobody acknowledged his work at that time. 6

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Introduction - 2  However Mendel's works received appreciation after 34 years of his research works.  In the year 0f 1900, Carl Correns of Germany, Hogo de Vries of Netherlands and Erich von Tscherma- Seysenegg of Austria realized Mendel's work as successful hybridization techniques among the pea plants and his study of heredity of specific traits among the pea plants. Gregor Mendel 1822 - 1884 7

8. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.8 Mendel's Laws-1  Mendel carried out series of series of experiments on pea plants.  He carried out different crosses between the pea plants differing with each other in single trait or multiple well defined traits.  By analyzing the phenotypes of offspring plants for chosen traits mathematically he put forth the three laws of genetics.  For these contributions to classical genetics Mendel is called as father of genetics. 8

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Mendel's Laws-2  Mendel put forth two laws of genetics which are also known as principles of Mendel. These laws are Law of segregation Law of independent assortment 9

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Mendel's Experiments on Pea Plants-1  Mendel carried out the numerous experiments involving various crosses among the pea plants in 1856.  Mendel carried out mathematical and statistical analysis to derive these laws of inheritance.  First Mendel obtained the true breeding plant for a single character say for example purple colored flower.  Thus Mendel obtained the true breeding plant for various traits (seven traits) by carrying out self fertilization. 10

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Mendel's Experiments on Pea Plants-2  Self fertilization to obtain true breeding plant for a single trait:- In self fertilization pollens from the anther are mixed with the stigma of the same flower. 11

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Mendel's Experiments on Pea Plants-3  After obtaining the true breeding plant (P generation)for a single trait, Mendel carried out cross fertilization among two true breeding plants which differ for a single trait.  The seeds obtained after such cross fertilization sown to produce plants which he referred to as filial generation or F1 generation.  He observed that the plants in F1 generations all show a single trait only (e.g. round seed). 12

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Mendel's Experiments on Pea Plants-4  Cross fertilization between true breeding plants which differ in a single trait. Cross fertilization involving mixing of pollens from one plant's flower with the ovules of another flower of another plants. 13

14. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.14 Mendel's Experiments on Pea Plants-5  All the plants produced after carrying out cross between the two true breeding plants which differ in a single trait, for example one plant with round seed and another with wrinkled seed were of the same phenotypes i.e. all plants of this F1 generations were having round seed. 14

15. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.15 Mendel's Experiments on Pea Plants-6 15

16. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.16 Mendel's Experiments on Pea Plants-7  Monohybrid cross:- Cross were carried out between the plants from F1 generation. In F2 generation 3:1 ratio was obtained i. e. three round seeds and one wrinkled seed were obtained. 16

17. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.17 Mendel's Experiments on Pea Plants-8  After obtaining the F1 generation plants, Mendel carried out cross fertilization between the plants from F1 generation; and obtained the plants which he referred to as plants of F2 generation.  He observed that plants of F2 generation showed mixed phenotypes; i.e. some plants are with round seeds and some plants were with wrinkled seed in characteristic ratio of 3:1(3 round:1 wrinkled). 17

18. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.18 Mendel's Experiments on Pea Plants-9  He further carried out self crosses between all round seed producing plants from F2 generation and observed that they produced plants with mixed phenotypes (in 3:1 ratio ).  Whereas the wrinkled seed producing plants from F2 generation when self- fertilized they produced all round seed producing plants or said to be true breeding plants. 18

19. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.19 Mendel's Experiments on Pea Plants-10  Mendel's conclusions:- Therefore Mendel concluded that the round seeds producing plants in F2 generation are not pure plants or true breeding plants for the trait of roundness of seed but are hybrid of both round as well as wrinkled seed traits. Therefore Mendel concluded that the trait for round seeds and trait for wrinkled seeds both are present in plants producing round seeds in F2 generation and they separate during self fertilization producing plants, some with round seeds and some with wrinkled seeds. 19

20. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.20 Mendel's Experiments on Pea Plants-11  Mendel's conclusions:- Mendel observed that in F2 generation all the phenotypes of P generation appear intact in a characteristic ratio i. e. 3:1. He observed that in F1 generation one parent's phenotype i. e. wrinkled seed was disappeared which reappeared in F2 generation. Therefore he concluded that trait controlling factors did not alter during fertilization and passed intact to the next generation. However some trait was masked in F1 generation; this masked trait again reappeared in F2 generation. 20

21. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.21 Mendel's Experiments on Pea Plants-12  Mendel's conclusion:- Mendel therefore referred to the trait which got expressed in F1 generation as Dominant trait and the trait which was masked in F1 generation and appeared in F2 generation as Recessive trait. This conclusion of Mendel form the explanation of the fact of Dominant trait. 21

22. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.22 Concept of Dominant Trait or Gene  In a pair of alleles of a gene, the allele whose phenotype is always expressed irrespective of its association with other allele is called as dominant allele of dominant gene. 22

23. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.23 Law of Segregation  Law of segregation state that each member of allelic genes get segregated or separated during gamete formation and thus the gamete contain only one member of alleles.  Mendel put forth this law by doing monohybrid cross between the two true breeding pea plants which differ in only one trait. 23

24. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.24 Law of Independent Assortment  The law of segregation state that during gamete formation the member genes of one alleles segregate independent of member gene of another alleles.  Mendel proved this law by carrying out dihybrid cross among the pea plants. 24

25. School of Science and Technology, Online Counseling Resource… What We Learn…..  The concept of alleles.  Concept of dominant genes and recessive genes.  Monohybrid cross.  Dihybrid cross.  Mendel’s first law of genetics.  Mendel’s second law of genetics. 25

26. School of Science and Technology, Online Counseling Resource… Critical Thinking Question  What were the innovative techniques that Mendel followed to formulate his principles of genetics? 26

27. School of Science and Technology, Online Counseling Resource… Hints For Critical Thinking Question  Preparation of true breed plants.  Fortunate selection of seven traits, all on different chromosomes. 27

28. School of Science and Technology, Online Counseling Resource… Study Tips  Book Title: Genetics Title: Genetics Author: Monroe W. Strickberger Author: Monroe W. Strickberger Publication: prentice-Hall of India private Limited Publication: prentice-Hall of India private Limited  Book Title: Principles of Genetics Author: Tamarin Author: Tamarin Publication: Tata Mcgrawhills Publication: Tata Mcgrawhills 28

29. End of the Presentation Thank You ! 29