Genetics and Genetic Diseases

Information about Genetics and Genetic Diseases

Published on October 15, 2008

Author: aSGuest1050



Genetics & Genetic Diseases : Genetics & Genetic Diseases Origins of Modern Genetics : Origins of Modern Genetics Gregor Mendel Studied inheritance of characteristics in garden peas Mendel’s First Experiment : Mendel’s First Experiment Mendel’s Conclusions : Mendel’s Conclusions Hereditary characters are determined by discrete factors (genes) Genes appear in pairs, one from each parent Genes can occur in different forms (alleles) If members of gene pair are different (heterozygous), one allele will express itself (dominant allele) and the other will not (recessive allele) Chromosomes : Chromosomes Mitosis : Mitosis Meiosis : Meiosis Chromosomes: Carriers of Genes : Chromosomes: Carriers of Genes Deoxyribonucleic Acid (DNA) : Deoxyribonucleic Acid (DNA) DNA Structure : DNA Structure DNA Replication : DNA Replication Genes and DNA : Genes and DNA Ribonucleic Acid : Ribonucleic Acid Protein Synthesis : Protein Synthesis Protein Synthesis : Protein Synthesis Protein StructuredeterminesProtein Function : Protein StructuredeterminesProtein Function Molecular Biology’s Central Dogma : Molecular Biology’s Central Dogma DNA RNA PROTEIN FUNCTION STRUCTURE Mendelian Inheritance : Mendelian Inheritance Autosomal Recessive Autosomal Dominant X-linked Recessive X-linked Dominant Y-linked Autosomal Recessive : Autosomal Recessive Either sex gets disease Siblings are usually affected, but not parents Heterozygotes of both sexes normal Heterozygote parents have diseased kids in ratio of 1:3 If defect involves a rare gene parents may be related Autosomal Recessive : Autosomal Recessive Galactosemia Tay-Sachs Disease Cystic Fibrosis Albinism Phenylketonuria (PKU) Sickle Cell Anemia Autosomal Dominant : Autosomal Dominant Affects males, females equally If you have the gene, you have the disease Every affected individual has an affected parent Normal siblings of affected individuals do not transmit disease (no unaffected “carriers”) Autosomal Dominant : Autosomal Dominant Polydactyly Achoo Syndrome Huntington’s Disease Achondroplastic Dwarfism X-linked Recessive : X-linked Recessive XA XA Xa Y Father’s Gametes Mother’s Gametes X-linked Recessive : X-linked Recessive XA Xa XA Y Father’s Gametes Mother’s Gametes X-linked Recessive : X-linked Recessive XA Xa Xa Y Father’s Gametes Mother’s Gametes X-linked Recessive : X-linked Recessive More frequent in males Passed from affected males through their daughters No transmission directly from father to son Female carriers can express phenotype at variable levels X-linked Recessive : X-linked Recessive Hemophilia Duchene Muscular Dystrophy Red/Green Colorblindness X-linked Dominant : X-linked Dominant Xa XA Xa Y Father’s Gametes Mother’s Gametes X-linked Dominant : X-linked Dominant XA Xa Xa Y Father’s Gametes Mother’s Gametes X-linked Dominant : X-linked Dominant Affected males with normal spouses have normal sons and all affected daughters All offspring have 50% chance of being affected X-linked Dominant : X-linked Dominant Faulty enamel trait Y-linked : Y-linked X X X Y Father’s Gametes Mother’s Gametes Y-linked : Y-linked Hairy ears Non-Mendelian Inheritance : Non-Mendelian Inheritance Mitochondrial Traits Mitochondria contain multiple copies of a single DNA strand All mitochondria transmit through ova Mitochondrial traits pass from mother to child Disorders involve combinations of CNS, eye, and muscle tissue abnormalities Non-Mendelian Inheritance : Non-Mendelian Inheritance Multifactorial Inheritance Do not involve single genes Pedigrees do not exhibit Mendelian patterns Frequently involve interaction between host, environmental factors Multifactorial Disorders : Multifactorial Disorders Congential Neural tube disorders Cleft lip, palette Congenital heart disease Multifactorial Disorders : Multifactorial Disorders Adult Coronary artery disease Type I diabetes Type II diabetes Breast cancer Colon cancer Lung cancer Rheumatic heart disease Alcoholism Multiple sclerosis Asthma, allergies Autoimmune disorders Bipolar disorder Schizophrenia Kidney stones Gallstones Obesity Peptic ulcer disease Gout Coronary Artery Disease : Coronary Artery Disease Blood pressure Cholesterol Triglycerides HDL Weight Glucose Hypercholesterolemia Diabetes mellitus Smoking Stress Inactivity Diet Oral Contraceptives Chromosomal Abnormalities : Chromosomal Abnormalities Euploidy : Euploidy Addition, loss of complete chromosome sets Monoploidy (N) Polyploidy Triploidy (3N) Tetraploidy (4N) Fatal to Embryo Aneuploidy : Aneuploidy Chromosome abnormalities not involving whole sets Trisomy-21 : Trisomy-21 Down’s Syndrome : Down’s Syndrome 1 in 600 births Short, broad nose Epicanthal fold Small oral cavity Large, furrowed tongue Large, irregular teeth IQs from 20 to 50 Trisomy 13 : Trisomy 13 Patau’s Syndrome : Patau’s Syndrome 1 in 20,000 births Sloping forehead Small head, eyes Cleft lip, palate Heart defects 75% die in first year 100% by age 6 Trisomy 18 : Trisomy 18 Edwards’ Syndrome : Edwards’ Syndrome 1 in 11,000 births Small mouth, jaw Low-set, malformed ears Clinched fist, index finger overlapping 3rd, 4th fingers Rocker-bottom feet Heart defects Hearing loss 90% die by age 1 Kleinfelter’s Syndrome : Kleinfelter’s Syndrome Kleinfelter’s Syndrome : Kleinfelter’s Syndrome 1 in 500 males Taller than average Partial breast development Small testicles, high-pitched voice, female hair distribution Altered body proportions, hips slightly larger than normal IQ about 90 Turner’s Syndrome : Turner’s Syndrome Turner’s Syndrome : Turner’s Syndrome 1 in 2500 females Grow slowly Shield chest when young Low hair line Widely spaced nipples Fail to menstruate, no ova Normal IQ; weakness in math, spatial perception Jacob’s Syndrome (XYY) : Jacob’s Syndrome (XYY) “Super Male” 1 in 1000 males 1 in 50 in prison populations Excessively tall (2/3s > 6 feet) IQs around 80 Low threshold for control of aggression X-Polysomy (XXX, XXXX) : X-Polysomy (XXX, XXXX) XXX, 1 in 1400 females Cannot be distinguished from XX females Problems with spontaneous abortions XXX have normal IQs, increasing numbers cause mental deficiency

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