PPT-Chromosomes and their disorders

Prepared by Rania Naoufal MD Learning Objectives Chromosome structure Chromatin Chromatin exists in several alternative configurations depending on what that particular stretch of DNA is doing. (Game from Univ. Utah). Siguna. Mueller. PhD student in BMS, Univ. Wyoming. What is DNA?. Each cell needs instructions for its role in the body. What do these instructions look like?. The instructions come in the form of a molecule called DNA.. A regular human cell has 46 chromosomes: 44 autosomes, which come in pairs, and 2 sex chromosomes, which specify gender (XX for female and XY for male).. The pairs of autosomes are called "homologous chromosomes." One of each pair came from mom and the other came from dad. Homologous chromosomes have all of the same genes arranged in the same order, but with slight differences in the DNA sequences of the genes.. Project goals:. identify. all the approximately 20,000-25,000 genes in human DNA. determine. sequences of the 3 billion chemical base pairs that make up human DNA. Karyotype. Genetic Disorders. Major types of genetic disorders:. CP Biology. Genetic Disorders. Major types of genetic disorders:. Autosomal. Single genes. Multiple genes. Sex-linked. Chromosome abnormalities. Autosomal Disorders. Autosomal genetic disorders . are caused by alleles on autosomes (chromosomes other than the sex chromosomes). Project goals:. identify. all the approximately 20,000-25,000 genes in human DNA. determine. sequences of the 3 billion chemical base pairs that make up human DNA. Karyotype. Genetic Disorders. Major types of genetic disorders:. What happens if mistakes occur?. Nondisjunction. When chromosomes fail to separate in meiosis. Lead to chromosomes disorders. Karyotype. Is an organized profile of a persons chromosomes. Two chromosomes specify gender:. Human Genes and Chromosomes. Chromosomes 21 and 22 are the smallest human autosomes. Chromosome 22 has about 43 million DNA base pairs. Chromosome 21 has about 32 million base pairs. . Chromosome 22 has about 545 different genes. Genetic disorders tat occur on chromosome 22 are leukemia and neurofibromatosis (a tumor causing disease). There is also a long stretch of repeating DNA that does not code for proteins. . Human Inheritance. Disorders caused by individual genes - dominant. Individuals with the disorder only need 1 allele to have the disorder. Huntington’s Disease. Caused by a repeat of the sequence CAG . .. Most common X-linked disorders.. Usually . expressed only in males.. Rarely, due to random X-inactivation, a female will express disease, called manifesting . heterozygotes. .. Pattern Of Inheritance:. Polydactyly. Down Syndrome. Hemophelia. Progeria. Hypertrichosis. Sickle Cell Anaemia. INTRODUCTION. What is genetic diseases/disorders?. The human body is composed up of cells , each one specializing a particular function like sensing light, smelling . For Premedical Student. 1438-1439H. Zoology Department. Lecture 24 : . Genetics. (. The Chromosomal Basis. of Inheritance). Objectives. Section B: Sex Chromosomes.. Some chromosomal systems of sex determination.. Human Chromosomes. Human chromosomes. 46 total, 23 pairs. 22 pairs of autosomes. 1 pair of sex chromosomes. Male vs. female. Human Chromosomes. Human chromosomes. 46 total, 23 pairs. 22 pairs of autosomes. LEC 3 genetic. Cytogenetic disorders: . Karyotype. . is a . paragraphic. representation of a stained metaphase spread in which the chromosomes are arranged in order of decreasing length.. Giemsa. stain . Complex Patterns of Inheritance. Incomplete dominance (review). Co-Dominance (review). Multiple alleles – pattern of inheritance is determined by two or more alleles. . Blood types (next slide) – three forms (I.