L2 Part I - Chromosomal basis of inheritance 2024 handout (1).pdf

Chromosomal basis of inheritance Chromosomes and their disorders 2024 Part (1) th Emery's Elements of Medical Genetics 16 edition 2022by Turnpenny and Ellard. (Chapter : 3 , Chromosomes and Cell Division) Page : 26 - 41 REFERE TO BOOK Definitions: gene - basic unit of heredity; codes for a spe...

Chromosomal basis of inheritance Chromosomes and their disorders 2024 Part (1) th Emery's Elements of Medical Genetics 16 edition 2022by Turnpenny and Ellard. (Chapter : 3 , Chromosomes and Cell Division) Page : 26 - 41 REFERE TO BOOK Definitions: gene - basic unit of heredity; codes for a specific trait. locus - the specific location of a gene on a chromosome (locus - plural loci). genome - the total hereditary endowment of DNA of a cell or organism. somatic cell - all body cells except reproductive cells. gamete - reproductive cells (i.e. sperm & eggs). chromosome - elongate cellular structure composed of DNA and protein they are the vehicles which carry DNA in cells. diploid (2n) - cellular condition where each chromosome type is represented by two homologous chromosomes. haploid (n) - cellular condition where each chromosome type is represented by only one chromosome. homologous chromosome - chromosome of the same size and shape which carry the same type of genes. chromatid - one of two duplicated chromosomes connected at the centromere. centromere - region of chromosome where microtubules attach during mitosis and meiosis The 46 chromosomes of human somatic cells constitute 23 pairs. Of those 23 pairs, 22 are a like in males and females and are called autosomes. The remaining pair comprises the sex chromosomes XX (female), XY (male). Chromosome structure: https://www.vedantu.com https://images.google.com Google Images. The most comprehensive image search on the web. Cell Division Refer To Book : Chapter 3 Chromosomes and Cell Division https://images.google.com Google Images. The most comprehensive image search on the web. https://images.google.com Google Images. The most comprehensive image search on the web Meiosis In germ cells Mitosis In somatic cells Daughter cells :4 Daughter cells: 2 Daughter cells have ½ the number of chr. of mother cell (23). Daughter cells have the number of chr. of mother cells (46) 2 chr. Of one pair move apart in 1st meiotic. Synapsis and crossing over Division of centromers and the two chromatids disjoin ------------------------- The consequences of meiosis: 1-Maintains a constant number of chromosomes from generation to generation. 2- Generates genetic diversity by assortment of chromosomes in meiosis I and by the process of crossing over of genetic material. Meiosis and fertilization introduce Genetic Diversity in two ways: 1-Crossing over between non sister chromatid of homologus chromosomes at prophase I. 2-Independent assortment (random) of homologus pairs at metaphase I https://socratic.org Cytogenetic studies = Cytogenetic analysis = Chromosomal analysis = Chromosomal studies = Karyotyping Classification of the chromosomes Refer To Book Chapter 3 Chromosomes and Cell Division Chromosomes are identified by their 1-size 2-centromere position 3-banding pattern. Size https://medlineplus.gov/genetics/understanding/basics/howmanychromosomes https://images.google.com Google Images. The most comprehensive image search on the web. Autosomes are numbered from largest to smallest. centromere position https://byjus.com/question-answer/identify-the-correct-match-between-the-type-of-chromosomes-and-theposition-of-the-centromere https://images.google. Google Images. The most comprehensive image search on the web. Metacentric chromosomes: 1, 3, 16 , 19, 20 Submetacentric chromosomes: 2,4,5, 6 - 12, 17,18 and X Acrocentric chromosomes: 13,14,15,21,22 and Y https://images.google.com Google Images. The most comprehensive image search on the web. Banding techniques: 1. G-banding 2. Q-banding 3. R-banding 4. C-banding G-banding  The technique most widely used in clinical cytogenetics laboratories. The chromosomes are treated first with trypsin to digest the chromosomal proteins and then with Giemsa stain. difference between karyogram and idiogram - Brainly.in 46,XY https://slideplayer.com How to write a cytogenetic karyotype 1- total number of chromosomes 2-sex chromosomes(XX or XY) 3- the chromosome number 4-either short arm (p) or long arm (q) 5-abnormality 6-region 7-band 8-sub-band e.g: 46 ,XY, 15 q 1 3 (normal male karyotype showing chromosome number 15 long arm region 1 band 3)