Chromosomes Labeling PDF

Chromosomes labeling 18 by Dr.Ezat Mersal At the end of this lecture, you will be able to:- 1. To define cytogenetic 2. To explain chromosome’s labeling 3. Cytogenetic Banding Nomenclature 4. Karyotype of DiGeorge Syndrome Chromosomes: Definition ...

Chromosomes labeling 18 by Dr.Ezat Mersal At the end of this lecture, you will be able to:- 1. To define cytogenetic 2. To explain chromosome’s labeling 3. Cytogenetic Banding Nomenclature 4. Karyotype of DiGeorge Syndrome Chromosomes: Definition  Genetic structures of cells containing DNA Identification  Each chromosome has a characteristic length and banding pattern © 2015 John Wiley & Sons, Inc. All rights reserved.  Each autosome is numbered from 1-22, sex chromosomes either X or Y © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved. Based on the three parameters of :  length,  position of the centromere,  and the presence or absence of satellites, chromosomes are subdivided into groups labelled A-G on the basis of overall morphology (A, 1-3; B, 4-5; C, 6- 12 + X; D, 13-15; E, 16-18; F, 19-20; G, 21-22 + Y). © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved. Example - 1q2.4  The first chromosome, long arm, second region of the chromosome, the fourth band of that sub-region © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved.  Normal male and female : 46,XY / 46,XX A male with Trisomy 21 : 47, XY, + 21 A female with Trisomy 21 : 47, XX, + 21 A female with a deletion of the short arm of one chromosome number 5: (Cri du Chat Syndrome) : 46, XX, del (5p) © 2015 John Wiley & Sons, Inc. All rights reserved. Definition  A photographic arrangement of a complete set of chromosomes of a cell or organism  Anarrangement of homologous pairs that decrease in size. © 2015 John Wiley & Sons, Inc. All rights reserved.  The analysis involves comparing chromosomes for their length, the placement of centromeres, and the location and sizes of G-bands. © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved. DiGeorge syndrome is typically due to the deletion of 30 to 40 genes genes in the middle of chromosome 22 at a location known as 22q11.2. chromosome 22 location Symptoms: Thymic aplasia aplasia Cleft palate Hypocalcemia/hypoparathyroidism Cardiac abnormality /Abnormal facies facies © 2015 John Wiley & Sons, Inc. All rights reserved. © 2015 John Wiley & Sons, Inc. All rights reserved.  Basic genetics : a human approach / BSCS. Dubuque, IA, Kendall/Hunt Pub. Co., c1999. 147 p. QH431.B305 1999  Genes, ethnicity, and ageing. Edited by Lincoln H. Schmitt, Leonard Freedman, Rayma Pervan. Nedlands, Australia, Centre for Human Biology, University of Western Australia ; Singapore, River Edge, NJ, World Scientific, c1995. 100 p.QH455.G45 1995  Genetic polymorphisms and susceptibility to disease. Edited by M. S. Miller and M. T. Cronin. New York, Taylor & Francis, 2000. 266 p.  GENETIC ANALYSIS AN INTEGRATED APPROACH Mark F. Sanders , John L. Bowman Second edition 2015 ISBN 978 0-321-94890-8 (student edition) www.pearsonhighered.com  Boundless Biology: Modern Understandings of Inheritance https://courses.lumenlearning.com/boundless- biology/  Anthony JF Griffiths, William M Gelbart, Jeffrey H Miller, and Richard C Lewontin (1999): modern genetic analysis