Understanding the Basics of Genetic Medicine Lecture 1 PDF

Pharos University in Alexandria Faculty of Physical therapy Pathology II PTBA - 333 UNDERSTANDING THE BASICS OF GENETIC MEDICINE Lecture 1 Dr /Maha Abubakr Feissal MD clinical hem...

Pharos University in Alexandria Faculty of Physical therapy Pathology II PTBA - 333 UNDERSTANDING THE BASICS OF GENETIC MEDICINE Lecture 1 Dr /Maha Abubakr Feissal MD clinical hematopathology Lecturer ILOs 1. Identify the terminology used in genetic medicine 2. Compare between codons & non-codons- Mutation & Allele 3. List steps of mitosis & meiosis. 4. Describe Mandela’s laws 5. Classify different chromosomal disorders Human genome, By 2003 the DNA sequence of the entire human genome was known  All of the approximately three billion base pairs of deoxyribonucleic acid (DNA) that make up the entire set of chromosomes of the human organism.  The human genome includes the coding regions of DNA, which encode all the genes (between 20,000 and 25,000) of the human organism, as well as the noncoding regions of DNA, which do not encode any genes. Human genome,  Is a collection of long polymers of DNA. That are maintained in duplicate copy in the form of chromosomes in every human cell and encode in their sequence of constituent bases (guanine [G], adenine [A], thymine [T], and cytosine [C]) the details of the molecular and physical characteristics that form the corresponding organism. Human genome,  The sequence of these polymers, their organization and structure, and the chemical modifications  Provide the machinery needed to: 1- Express the information held within the genome 2- Provide the genome with the capability to replicate, repair, package, and otherwise maintain itself 3-Essential for the survival of the human organism; without it no cell or tissue could live beyond a short period of time  WHAT IS CHROMOSOME ? CHROMOSOME consists of: 70% protein - 20% DNA – 10% RNA SOMATIC CELLS GAMETES (SEX CELLS) 23 PAIRS OF CHROMOSOMES 23 CHROMOSOMES (46 CHROMOSOMES) HAPLOID DIPLOID http://64.40.115.136.van.ca.siteprotect.com/ 23 PAIRS IN MITOSIS HUMANS diploid Mitosis is the process by which an animal cell, which has previously replicated each of its chromosomes, separates the chromosomes in its cell nucleus into two identical sets of chromosomes, each set in its own new nucleus  ACTIVITY #1 MITOSIS I n. Can you identify cells in each stage of mitosis? http://cherlyncreative2biology.blogspot.com/  MEIOSIS Sex cells are produced by meiosis. diploid In humans, meiosis reduces the number of chromosomes from 46 (23 pairs) to 23 (single). in humans n = 23 haploid http://bio.rutgers.edu/ INHERITANCE AND GENETIC DIVERSITY DIPLOID diploid CELL 2n HAPLOID haploid CELL 1n diploid Errors in meiosis can occur ALLELE  A variant of DNA sequence at a given locus  The Genotype of each gene compromises the pair of alleles present in that locus  Dominant Allele: Allele that leads to an observed phenotype  Recessive Alleles Allele that does not lead to an observed phenotype  GENETIC DIVERSITY allele for allele for blood type O blood type A locus for blood type gene Homologous chromosomes are chromosome pairs with genes for the same characteristic. An allele is one of the alternative forms of the same gene. GENOTYPE: A A A O O O homozygous heterozygous homozygous PHENOTYPE: (BLOOD TYPE) A A O allele A is DOMINANT allele O is RECESSIVE  Genetic Disorders  Genetic disorders are due to alterations or abnormalities in the genome of an organism.  A genetic disorder may be caused by a mutation in a single gene or multiple genes. It can also be due to changes in the number or structure of chromosomes.  Genes are the basic unit of heredity, hold the genetic information in the form of DNA which can be translated into useful proteins to carry out life processes  These genes undergo a mutation sometimes, which changes the instructions to formulate the protein, which does not work properly.  Genetic disorders are caused by one or more abnormalities in one or more genes. We have 23 pair of chromosomes…Chromosomes are…genes are…gene/DNA to RNA to protein Major Chromosomal disorders A Numerical Abnormality: Ploidy = Euploid Aneuploidy Polyploidy Monosomy Trisomy Mosaicism ( 2 or more population of a cell)  Major Chromosomal disorders B Structural Abnormality: Translocation Isochromosome Inversions Deletion Insertions Ring Chromosome Activity Simple Mendelian diseases Multifactorial / Complex diseases Dr /Maha Abubakr Feissal MD clinical hematopathology Lecturer