* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download human genetics - local.brookings.k12.sd.us
Medical genetics wikipedia , lookup
Genetic engineering wikipedia , lookup
Genome evolution wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Gene nomenclature wikipedia , lookup
Gene expression programming wikipedia , lookup
Gene therapy wikipedia , lookup
Y chromosome wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Down syndrome wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
DiGeorge syndrome wikipedia , lookup
Neocentromere wikipedia , lookup
Oncogenomics wikipedia , lookup
Designer baby wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Genome (book) wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
X-inactivation wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Frameshift mutation wikipedia , lookup
HUMAN GENETICS What can go wrong? Chromosome Mutations Gene Mutations Chromosomal Abnormalities • 1 infant in 200 newborns has a chromosomal abnormality • 28% of first trimester miscarriages have a chromosomal abnormality • Abnormalities in larger chromosomes don’t usually survive A change in the DNA code of an organism is called a ______________________ MUTATION Mutations can be HARMFUL BENEFICIAL OR ______________ _______________ BENEFICIAL MUTATIONS Help an organism survive and reproduce Provide variation in population for natural selection to act upon Image from: http://www.cheryllavender.com/Snow%20Rabbit.jpg HARMFUL MUTATIONS Can result in death =___________ LETHAL (even before birth) Cause a genetic disorder Cause cancer SOMATIC CELL MUTATIONS If the change happens in a BODY CELL (lung, liver, brain, muscle, etc.) = ______________________ Somatic cell mutation Somatic cell mutations can: Cause cancer ______________________ Make cell not able to function ______________________ Kill cell _____________ BUT won’t be passed on to offspring GERM CELL MUTATION If the change happens in Gametes (sperm & eggs) = _______________________ Germ cell mutation Can be passed on to offspring HUMAN GENETICS What can go wrong? Chromosome Mutations Gene Mutations Changes in chromosome number Missing chromosomes (monosomy) ____________________________ EX: Turner’s syndrome - X0 Extra chromosomes (trisomy) ____________________________ EX: Down’s syndrome – 3 #21’s Kleinfelter’s syndrome- XXy NON-DISJUNCTION A homologous pair sticks together and doesn’t separate at MEIOSIS. One cell gets 2 copies of the chromosome the other cell gets none. Normal Meiosis Nondisjunction Nondisjunction • Chromosomes don’t separate at anaphase • Cell gets 2 copies of a chromosome OR none • After fertilization new baby gets 3 of each chromosome (trisomy) or only 1 copy of each (monosomy) Normal division Non-disjunction Human Abnormalities Caused by Non-Disjunction Down’s syndrome Patau syndrome Kleinfelter syndrome Turner’s syndrome Xyy Turner’s syndrome (monosomy) Turner’s syndrome XO • • • • • • • • 1 in 5000 births Female = XO Small size Slightly decreased intelligence 35% have heart abnormalities Hearing loss common Broad chest Undeveloped ovaries/can’t have children Kleinfelter syndrome Xxy (trisomy) Kleinfelter syndrome • 1 in 1000 births • Male = XXy • Average to slight decrease in intelligence • Small testes/ can’t have children • Usually not discovered until puberty when don’t mature like peers Xyy syndrome • Xyy males • Taller • Average intelligence • Some study show increased learning disabilities • Lead normal lives Down’s syndrome (trisomy 21) Down’s syndrome (trisomy 21) • 1 in 660 births • Similar facial features • Slanted eyes • Protruding tongue Down’s syndrome (trisomy 21) Simian line on palm Down’s syndrome (trisomy 21) • Most common chromosomal abnormality • 50% have heart defects that need surgery to repair • Mental retardation • Risk increases with age of mom Patau syndrome (trisomy 13) Patau syndrome (trisomy 13) • Can be traced back 300 years in literature • 1st identified as a chromosomal cause in 1960 • 1 in 7000 births (rare) Patau syndrome (trisomy 13) Cleft lip & palate Eye abnormalities (too small or missing) Patau syndrome (trisomy 13) Low set ears Polydactyly HUMAN GENETICS What can go wrong? Chromosome Mutations Gene Mutations DELETION ________________________________________ Piece of whole chromosome is lost Image from: http://www.biology-online.org/2/8_mutations.htm Human Abnormalities Caused by Deletions • Wolf-Hirschhorn syndrome • Cri-du-chat syndrome • Prader-Willi Syndrome Wolf-Hirschhorn syndrome (4p-) • Missing piece on short arm of chromosome 4 • Mental retardation • Large low set ears • Club feet Cri-du-chat (Cat cry) (5p-) • 1 in 50,000 births • More common in girls • Mewing cry in infancy • Missing piece of number 5 • Mental retardation • 50% have heart defects Prader-Willi Syndrome • Deletion in chromosome 15 • Feeding problems: poor weight gain in infancy, won’t eat • Ages 1-6 excessive, rapid weight gain • Under developed sex organs • Mild to moderate retardation • Obsession with food • Complications from problems associated with obesity (heart attack, high blood pressure, diabetes) Prader-Willi syndrome Victor at age 1 Victor at age 2 INVERSION Segment flips and reads backwards Image from: http://www.biology-online.org/2/8_mutations.htm TRANSLOCATION Segment breaks off and joins a different non-homologous chromosome Image from: http://www.biology-online.org/2/8_mutations.htm A gene that is flipped and reads backwards will not work. A gene that is moved to another chromosome will not separate from its partner during meiosis. One cell can get 2 copies of gene, one cell gets none. HUMAN GENETICS What can go wrong? Chromosome Mutations Gene Mutations GENE MUTATIONS Changes in the DNA code of a single gene PROTEIN DNA RNA ____________ ______________________ ___________ Harmful Gene Mutations 1. Point mutations – changes a _________ SINGLE base in DNA code 1. __________________ Substitution 2. Frame shift mutations changes _____________ MULTIPLE bases in code Deletion 1. ___________________ 2. ________________ Addition SUBSTITUTION Changes one base for another ATT C GAG C T ATT C TAG C T SICKLE CELL ANEMIA CAUSE: (autosomal recessive) A changed to T (glu to val) gene on chromosome #11 that codes for part of hemoglobin protein (carries oxygen in blood) SICKLE CELL ANEMIA SYMPTOMS: Sickle shaped Red Blood Cells in hh persons Circulatory problems Loss of blood cells (anemia) Organ damage DEATH SICKLE CELL ANEMIA More common in African Americans 1 in 500 = hh 1 in 10 = Hh carriers for gene Hh persons have Sickle cell TRAIT make some normal RBC’s’ ; some sickled cells FRAME SHIFT MUTATIONS Changes multiple bases in code thefatcatranandran the fat cat ran and ran ____________________ DELETION theatcatranandran the atc atr ana ndr an _____________________ FRAME SHIFT MUTATIONS at beginning of gene are more damaging than those at end because more of gene is changed thefatcatranandran ____________________ the fat cat ran and ran DELETION near front theatcatranandran the atc atr ana ndr an _____________________ DELETION near end thefatcatranandrn _____________________ DELETION ________________________________________ Piece of DNA code for one gene is lost Image from: http://www.biology-online.org/2/8_mutations.htm Duchenne Muscular Dystrophy CAUSE: (X linked recessive) DELETION in gene that codes for a muscle protein Duchenne Muscular Dystrophy (DMD) SYMPTOMS: 1 in 3500 male births Appears before age 5 Progressive muscle weakening Most in wheelchair by age 13 Eventually lethal DUPLICATION Piece of DNA is copied too many times ________________________________________________ Image from: http://www.biology-online.org/2/8_mutations.htm FRAME SHIFT MUTATIONS Changes multiple bases in code thefatcatranandran the fat cat ran and ran ____________________ DUPLICATION thefatcatranandandandandran the fat cat ran and and and ran ___________________________ HUNTINGTON’S CAUSE: Autosomal dominant 40-100 CAG Repeats at end of gene on chromosome 4 HUNTINGTON’S SYMPTOMS: Seen in both males and females • Degenerative brain disorder • Symptoms appear age 30-40 (Usually after having children) • Lose ability to walk, think, talk, reason • 50/50 chance of passing it to child Until now people didn’t know they had the gene, until after they had already had children. Now there is a test to tell if you have the gene before symptoms appear. Would you want to know if there is NO cure? OTHER GENETIC DISEASES AUTOSOMAL RECESSIVE • Phenylketonuria • Cystic fibrosis • Albinism X-LINKED RECESSIVE • Color blindness • Hemophilia • Muscular dystrophy AUTOSOMAL DOMINANT • Achondroplasia (Dwarfism) • Huntington’s HEMOPHILIA CAUSE: change in gene on X chromosome that codes for blood clotting protein SYMPTOMS: More common in males Internal and external bleeding Can result in death transfusions/hospitalization required frequently to stop bleeding ACHONDROPLASIA (Dwarfism) CAUSE: (Autosomal Dominant on chromosome 4) Most are new mutations in egg or sperm cell, but it can be inherited from parent with gene 1 in 20,000 births 200,000 “little people” worldwide One of oldest known – seen in Egyptian art Normal size torso; short arms and legs Problem with way cartilage changes to bone as bones grow COLOR BLINDNESS CAUSE: X linked recessive Mutation in gene on X chromosome SYMPTOMS: More common in males (8% of males are colorblind) Can’t distinguish certain colors Most common = red/green Cystic Fibrosis Mutation in gene on chromosome 7 that codes for protein in membrane that transports chloride ions Cystic Fibrosis Autosomal recessive Symptoms: More common in Caucasians Make extra thick mucous in lungs and pancreas which leads to respiratory and digestive complications Salty skin is clue Phenylketonuria (PKU) CAUSE: Mutation in gene for enzyme that changes the amino acid phenylalanine into tyrosine Build up causes brain damage ALL babies have blood test for PKU when born before leaving hospital Treatment: Diet low in phenylalanine can extend life and prevent retardation * Nutri-sweet warning All “SUGAR-FREE” foods have a warning label * PHENYLKETONURICS: Contains phenylalanine Image from: http://www.themagicgadget.co.uk/xcart/search.php?mode=search