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

2. OC-SBT092-CP1-05 Introduction Programmes and Courses  SEP – SBT092 – Unit 01 - 05

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… © 2009, 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… © 2009, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Describe karyotyping of human chromosomes Describe chromosomal banding Describe applications of karyotyping and chromosomal banding 5

6. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.6 Introduction  Characterization of chromosomes in non dividing cells give lot of cytogenetic information of the chromosomes.  This characterization of chromosome is referred to as karyotyping.  Karyotype of normal member of a species is unique.  Studying the deviations or abnormalities in karyotypes help cytogenetist diagnose number of genetic diseases.  In this modules students shall learn about karyotyping with the help of banding techniques. 6

7. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.7 Karyotyping of Chromosomes-1  Karyotyping:-  It is defined as characterization of chromosome complements with respective to their size, shapes, types and number with the help of chromosome banding techniques.  Karyotyping is carried out during metaphase of cells.  Karyotype is referred to the photomicrograph in which chromosomes are arranged in homologous pairs and descending order of their size. 7

8. School of Science and Technology, Online Counseling Resource… Karyotyping of Chromosomes-2  karyotype/karyogram of human chromosomes:-  grouping of chromosomes-- 8© 2009, YCMOU. All Rights Reserved.

9. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.9 Karyotyping of Chromosomes-3  Karyotyping:-  Karyotype is used to study chromosomal aberrations, evolutionary relationships between closely related species, cellular functions and taxonomic relationship.  Karyotyping is carried out during metaphase by arresting replication of chromosome by colchicine.  The chromosomes are then stained using different types of special dyes which give characteristic bandings on chromosomes. 9

10. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.10 Karyotyping of Chromosomes-4  Karyotyping:-  Karyotyping help diagnose number of congenital diseases and syndromes caused by chromosomal aberrations.  Karyotyping involves following steps :  preparation of tissue cultures of bone marrow cells, fibroblasts, peripheral blood cells, skin cells etc,  Arresting the mitosis at metaphase of nuclear division by colchicine in hypotonic solution.  Use of mitogenic agent such as phytohemagglutinin.  Staining of chromosomes 10

11. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.11 Chromosomal Banding-1  Chromosomal banding:-  Use chromosomes at metaphase  Use special staining dyes such as Giemsa, quinacrine mustard.  Detect finer chromosomal aberrations such as deletion, translocations and inversions.  Detect morphological defects and number of chromosomes in diploid cells. 11

12. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.12 Chromosomal Banding-2  Types of banding techniques:  Number of banding techniques depending upon the dyes used and the outcomes of the techniques.  Q banding  G banding  C banding  R banding  T banding 12

13. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.13 Chromosomal Banding-3  Q banding:-  Uses quinacrine mustard dye  show substructures along the length of chromosomes  G banding:-  Uses Giemsa stain  Show structural abnormalities  Both Q and G banding chromomeres observed in leptotene and pachytene chromosomes during meiosis. 13

14. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.14 Chromosomal Banding-4  Q and G banding:-  On the basis of banding patterns three major types of chromatins can be identified which are as follow:  Centrometric or kinetochoric heterochromatins  Intercalary heterochromatins  Euchromatins 14

15. School of Science and Technology, Online Counseling Resource… © 2009, YCMOU. All Rights Reserved.15 Chromosomal Banding-5  C banding:-  Involve partial denaturation chromosomes  Gives intense and differential staining due to rapid reannealing of satellite DNA located in kinetochoric region of chromosomes.  Satellite DNA – short highly repetitive nucleotide sequences  Varies from person to person in human due to presence of variable amount of satellite DNA.  Used to study polymorphism in human chromosomes. 15

16. School of Science and Technology, Online Counseling Resource… Chromosomal Banding-6 C banding:- banding at kinetochoric region 16© 2009, YCMOU. All Rights Reserved.

17. School of Science and Technology, Online Counseling Resource… Chromosomal Banding-7  R banding:-  R banding is reversed banding pattern that of Q and G banding.  R banding is due to staining of GC rich segments of chromosomes.  R banding is obtained by mild heat treatment before the application of Giemasa stains.  Useful for detecting deletion and translocation mutations in telemore region of chromosomes 17© 2009, YCMOU. All Rights Reserved.

18. School of Science and Technology, Online Counseling Resource… Chromosomal Banding-8  T banding:-  Involve mild heat treatment  Use of Giemsa and acridine orange dye  Staining of telemoric regions of chromosomes.  Smaller than R bands.  Use for cytogenetic analysis 18© 2009, YCMOU. All Rights Reserved.

19. School of Science and Technology, Online Counseling Resource… What We Learn…  Karyotyping of human chromosomes  Principle of technique of karyotyping  Chromosomal staining –chromosomal banding  Applications of karyotyping  Applications of chromosomal banding 19© 2009, YCMOU. All Rights Reserved.

20. School of Science and Technology, Online Counseling Resource… Critical Thinking Questions  Why chromosomal banding is carried out in cells’ metaphase only? 20© 2009, YCMOU. All Rights Reserved.

21. School of Science and Technology, Online Counseling Resource… Tips For Critical Thinking Questions  Chromatids are visible  Chromosomes are duplicated 21

22. School of Science and Technology, Online Counseling Resource… 22 Study Tips  Book Title: Molecular Biology of the Gene Title: Molecular Biology of the Gene Author: Author: Watson, baker et al. Publication: Publication: Pearson Education Ltd. Book Title: Genetics Title: Genetics Author: C. B. Pawar Author: C. B. Pawar Publication: Publication: -- © 2009, YCMOU. All Rights Reserved.

23. End of the Presentation Thank You ! 23 © 2009, YCMOU. All Rights Reserved.