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-CP1-05 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  Counsellor at each study centre should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counselling  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 various types of chromosomal variations. Describe the mechanisms of various types of chromosomal variations and mutations. Describe the significance of chromosomal variation. 5

6. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.6 Introduction - 1  In animals chromosomal variation during meiosis is main reason of phenotypic diversities observed in animals  Chromosomal variation caused by interspecies breeding leads to emergence of new species in plants.  Chromosomal variations in plants are useful in plants since it lead to generation of high yield producing plants.  Some chromosomal variations cause genetic diseases in human.  In this presentation students will learn different types of chromosomal variations. 6

7. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.7 Chromosomal Variations  Chromosomal mutations occur due to two main mechanisms: Due to changed in number of chromosomes  The chromosomal number change is brought about by the mechanism of non disjunction of chromatids at the time of their separation during meiosis or mitosis. The abnormal change in the chromosome number giving rise to this type of mutations is known as aneuploidy.  Due to change in arrangement of nucleotide, length and structure of chromosomes. 7

8. School of Science and Technology, Online Counseling Resource… 8 Chromosomal Variations  The chromosomal variation can occur due to change in the entire set of chromosome (Polyploidy) of change in number of a single chromosome (Aneuploidy).  The chromosomal variations are common in plants and Commercially beneficial since these lead to increase in yield.  The chromosomal variations are common in plants because the Aneuploid and polyploid plants can survive and propagate through asexual mean though the sexual reproduction is stoped in them due to these chromosomal variations.  The aneuploidy and polyploidy is not common in animals since they Reproduce only by sexual mean and the aneuploid and polyploid zygote do not survive most of the time in animals.

9. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.9 Chromosomal Mutations-2  Chromosomal mutations due to structural and nucleotide sequence change in chromosomes:- – Due to deletion of nucleotide sequence 9

10. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.10 Chromosomal Mutations-3 (2) Due to duplication of nucleotide sequence: 10

11. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.11 Chromosomal Mutations-4 (3) Due to trans location of nucleotide sequence: 11

12. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.12 Chromosomal Mutations-5 (4) Due to inversion of nucleotide sequence: 12

13. School of Science and Technology, Online Counseling Resource… © 2007, YCMOU. All Rights Reserved.13 Chromosomal Mutations-6 (5) Due to break in the intact structure of chromosome: 13

14. School of Science and Technology, Online Counseling Resource… Chromosomal Mutations-7 chromosomal mutations can also be generated by transposable elements. crossing over between the transposable elements lead duplication and deletion type of chromosomal mutations. 14

15. School of Science and Technology, Online Counseling Resource… Chromosomal Mutations-8 movement of transposable element to new location on chromosome can alter the expression of gene at that location leading to chromosomal mutation. 15

16. School of Science and Technology, Online Counseling Resource… Chromosomal Mutations-9 The inheritance of genetic disorder produced by chromosomal mutations can be studied by pedigree analysis. where square represent male and circle represent female. Horizontal line represents breeding between male and female. And Vertical line represent denotes to their offspring. 16

17. School of Science and Technology, Online Counseling Resource… What We Learn…..  The chromosomal variations  Various mechanisms of generation of chromosomal variations.  Phenotypic effects of chromosomal variations. 17

18. School of Science and Technology, Online Counseling Resource… Critical Thinking Question  Why meiosis is said to be main cause of chromosomal variation? 18

19. School of Science and Technology, Online Counseling Resource… Hint for Critical Thinking Question  Genetic recombination.  Homologous chromosomes. 19

20. 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 20

21. End of the Presentation Thank You ! 21