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Multifactorial traits
traits affected by both gene and environmentEnvironmental factors affect phenotypes: Prenatal environment What we eat and breathe Where we live Infections TERM 2
Environmental factors and phenotypes
DEFINITION 2 The ability to taste PTC has a genetic basis.there are variations in Responses to Drugs and Medicines TERM 3
Relationship between Cancer and
Environment
DEFINITION 3 Some environmental factors implicated in cancer Natural radiation (x-rays, radon gas) Occupational exposure to chemicals (PVC, benzene, andsynthetic pesticide) Viral infections (Hepatitis B and Human Papillomavirus) Personal choices: exposure to UV, smoking and diet (toomuch cooked meat)In most cases, other factors are involved in conversion of anormal cell to a cancer cell by viral infection: DNA damage TERM 4
Cancer and Viral Infection
DEFINITION 4 Viral infections account for almost 15% of cancersworldwide.HPVHep B TERM 5
Serotonin
DEFINITION 5 released into synapse to transfer nerve signal to post- synaptic neuron responsible for reuptake of serotonin into the presynaptic cell
Genes and Behavior
5-HTT responsible for depressioncodes for seritonin transporter 5- hydroxy- tryptamine transported proteinsuggested both genetic factor (polymorphism in 5- HTT) and environmental factor (stress) can influence behavior TERM 7
Autoimmune diseases
(AID)
DEFINITION 7 3rd most common conditions in US Over 75% of patients are women (unknown reason) Occurs when immune system produce antibodiesabnormally Attack cells and tissues, including skin, connective tissues,digestive system, and nervous system Diabetes, multiple sclerosis, rheumatoid arthritis, and more Both genetic (presence of specific allele) and environmentalfactors (infections) are involved in triggering these diseases TERM 8
Polygenic Traits
DEFINITION 8 Examples: color of skin, hair, and eyes, and immune system Immune system have at least 30 million different genotypes by acombination of many alleles of multiple genesBell curve distribution: Trait values for most people are clustered at ~average Few individuals clustered at extremes of the phenotype TERM 9
Variations in Skin Color
DEFINITION 9 Melanin: Skin pigmentation produced by melanocytes (skin cells) Protects skin (partially) from UV Provides skin color Skin color is a phenotype resultingfrom interaction b/w pigment genesand environment (UV exposure) TERM 10
Characteristics of Multifactorial Traits
DEFINITION 10
- Several genes control a trait2. Trait is not inherited as dominant or recessive There are many phenotypic differences in trait within a population form a bell-shape curve Each gene is inherited in Mendelian fashion3. Genes controlling trait contribute a small amount to thephenotype As the number of genes controlling trait increases, phenotypicdifferences among people decreases4. Environmental factors interact with gene to produce phenotype
Concordance
is calculation of the presence of a trait in both members of twins Percentage that a pair of twins have same trait in bothmembers Concordance rate (%) = [both affected / (one affected + both affected)] x 100 Obesity occurs in both MZ twins ~70% of the time:70% concordance Helps establish whether or to what extent it is caused bygenetic mutation - determine heritability TERM 17
Cleft palate/lip
DEFINITION 17 Results from failure of nose and jaw structures to meet and fuseduring development Very treatable condition these daysexample of threshold model TERM 18
Heritability
Values
DEFINITION 18 Heritability score = 1.0 trait variability is completely result of gene action, and no environmental impact TERM 19
Spina
Bifida
DEFINITION 19 Lower (tail side; caudal) end of the neural tube does not close Opening and damage can be surgically repaired, but damage tonervous system is permanent Children born with this condition have various degree of paralysisdepending on which portion of the neural tube is open Most individuals have learning disabilities May have bowel and bladder problems No cure for SB but most live into adulthoodTends to cluster in families Environmental factors include dietary deficiencies in folic acid TERM 20
Development of Neural Tissues
DEFINITION 20 In early stage of embryonic development, dorsal ectoderm folds toform neural tube Neural tube gives rise to the central nervous system (CNS), brain and spinal cord Bidirectional fusion of neural tube begins in mid cervical area proceeds rostrally and caudally closed neural tube with fusion (21 to 28 days) Neural tube defects (NTDs)1. Anencephaly failure of neural closure at upper region2. Spinal Bifida failure of neural closure at lower region
Anencephaly
Most extreme form of neural tube defects Upper (head side; cranial) end of the neural tube does not close Major portions of brain and skull do not form Remaining portions of the brain may not be enclosed in skull Can survive only within mother, most stillborn TERM 22
Folic Acid
DEFINITION 22 Dietary supplementation with folic acid has been shownto be helpful in preventing spina bifida TERM 23
VANGL1: Genetic factor of NTD
DEFINITION 23 VANGL1 gene associated with neural tube defects located on one end of chromosome 1 In mice, gene is implicated in early development of neural tube Mutations in gene cause conditions similar to SB A study of > 100 patients with neural tube defects showed affected individuals had mutations in VANGL TERM 24
Body Weight - Obesity
DEFINITION 24 Twin studies suggest obesity has 70% concordance in MZ and 30% concordance in DZ Environmental components such as lifestyle, including diet and exercise impact body weight Genetic factor leptin and more genes (polygenic trait) Although Leptin is involved in obesity, mutation of this gene account for only a small portion of obesity (in human) Dramatic increase of people with obesity over the last 30-40 years cannot account for only genetic factors TERM 25
Cancer
DEFINITION 25 Uncontrolled cell division Malignant (cancerous) cells spread to and invade other tissues in the body
Cancer Cells
Small cytoplasm Multiple nuclei Multiple & large nucleoli Coarse chromatin TERM 32
Characteristics of Cancer
DEFINITION 32 i. Tumors cells divide continuously by uncontrolled mitosisii. Metastasis: TERM 33
Metastasis
DEFINITION 33 Cells move to other sites in the body Cells are invasive1. Cancer cells break off of tumor2. Cancer cells attach to the wall of a blood vessel and secrete enzymes that create an opening in the vessel3. Cancer cells enter the blood and are carried along to other parts of the body TERM 34
Carcinogens
DEFINITION 34 (environmental factors) and certain behaviors increase rate of mutations and cancer risk UV light, chemicals, and virus infection Diet and smoking TERM 35
How Are Genes Involved with Cancer
DEFINITION 35 Two classes of genes cause cells to become cancerous when they mutate: Oncogenes Mutated tumor suppressor genes These genes play a role to control cell division in normal cells in opposite ways Proto-oncogenes: turn ON cell division Tumor suppressor genes: turn OFF cell division
Breast Cancer
Most common form of cancer in US womenMutations in BRCA1 and BRCA2 can predispose women to breast cancer and ovarian cancergenetic marker on chromosome 1782% of women with one mutant BRAC1 allele will develop secondmutation in another allele and get breast cancer TERM 37
Philadelphia chromosome
DEFINITION 37 Translocation b/w chromosomes 9 and 22 (9; 22) Common in chronic myelogenous leukem TERM 38
Cancer cluster
DEFINITION 38 large number of cancer cases found in restricted area Cancer cluster in Woburn, Massachusetts Environmental trigger causing cancer - industrial solvents(TCE and PCE) that entered the towns water supply (1970s) TERM 39
Vegetables Lower Cancer Risk
DEFINITION 39 Heterocyclic aromatic amines are formed in over-cooked meat. These are associated with colon cancer. Cruciferous vegetables activate enzymes that block this pathway, are protective against colon cancer. TERM 40
Smoking
DEFINITION 40 Number one environmental factor implicated in lung and bronchus cancer either direct (smoker) or indirect (secondhand smoke) Related to cancers of oral cavity, larynx, esophagus, and lungs Accounts for 30% of all cancer deaths Most these cancer have very low survival rate Snuff or chewing tobacco users 50X morelikely to develop cancer of the mouth
Neurotransmitters
Brain chemicals released from one nerve cell (pre-synaptic neuron) into synapses bind to the receptors of the next nerve cell (post-synaptic neuron) become active transmit nerve impulse (~ 100 m/sec) This process is called neurotransmission Increase or decrease in release of neurotransmitter maychange behavior such as moods and actions TERM 47
Endorphins
DEFINITION 47 Neurotransmitter During exercise, stress, or excitement, brainreleases endorphins We feel a rush of exhilaration TERM 48
Single-gene Defects and behavior
DEFINITION 48 Example of single-gene defect that changes behavior: Huntington disease (HD) HD gene encodes Huntingtin protein Necessary for the survival of certain brain cells Symptoms of HD: Involuntary movements Progressive personality changes TERM 49
Schizophrenia
DEFINITION 49 Typically early adult onset disorders Characterized by Eccentric behavior and anomalies of thinking Loss of ability to organize thoughts and perceptions Progression with many symptoms; Difficulty paying attention Memory and learning difficulties Disorganized speech Hallucinations and DelusionsGenes associated with schizophrenia found on X chromosome and other autosomes TERM 50
Major Depressive Disorder
DEFINITION 50 Marked by unexplained lethargy, sadness, and chronicdepression
Bipolar Disorder
Marked by "mood swings" between maniaand depression 5. million American adults affected (NIMH) Symptoms of mania phase: Hyperactive restlessness Rush of ideas Greatly expanded libido Fantastic ideations Recklessness, substance abuse and thrill seeking TERM 52
Eating Disorders
DEFINITION 52 Researchers are focusing in on genes that controlappetite and energy storage There may be not an specific anorexic gene, but rather agenetic combination that confers a susceptibility. Candidates: Genes encoding proteins that control appetite Leptin Leptin receptor Genes of neurotransmitters Dopamine Serotonin TERM 53
MAOA Deficiency
DEFINITION 53 A gene for this condition was mapped to short arm of Xchromosome X-linked trait Monoamine oxidase type A (MAOA) breaks downneurotransmitters, serotonin and dopamine in brain Mutated gene causes MAOA deficiency Unable to breakdown neurotransmitters Normal transmission is disrupted Cause abnormal behavior TERM 54
Antidepressant Medicines
DEFINITION 54 Serotonin (5-HT) can affect mood, emotion, appetite, and sleep Drugs selective serotonin reuptake inhibitors (SSRIs) SSRI antidepressants - block 5-HT reuptake transporter Fluoxetine (Prozac, Fontex, Seromex, Seronil, Sarafem, Fluctin) Citalopram (Celexa, Cipramil, Emocal, Sepram) Escitalopram oxalate (Lexapro, Cipralex, Esertia) Sertraline (Zoloft, Lustral, Serlain TERM 55
Richard Speck
DEFINITION 55 Tried and convicted of killing 8 student nurses inChicago Attorney prepared defense trying to use XYY karyotypeas argument against death penalty Speck did not have the XYY karyotype
T cells
mature in the thymus gland Cytotoxic T cells: directly attack foreign cells (cell-mediatedimmunity) Helper T cells: release interleukins to activate B cells TERM 62
B cells
DEFINITION 62 released from spleen and lymph nodes Plasma cells: release antibodies (humoral immunity) Memory cells: allow for stronger response to subsequent attack TERM 63
Macrophages
DEFINITION 63 engulf invaders (bacteria or virus) to digest them stimulate proliferation of helper T cells TERM 64
Antigens
DEFINITION 64 Foreign molecules (agents) detected by immunesystem Foreign cells or proteins Disease-causing agents - virus, bacteria, fungus TERM 65
Immune Response
DEFINITION 65 Once immune system detects antigens, a series ofreactions are triggered Several stages of trigger response:1. Detection of antigen activates T4 helper cell2. Activated T4 helper cells activate B cells3. Activated B cells produce and secrete protein antibodies4. Antibodies bind to antigen (marking)5. White blood cells (leukocytes) attack bacteria marked by antibodies6. Memory cells rapid and massive response on second exposure to the same antigen
Antibody Structure
Y-shape Consist of 4 proteins; 2 long heavy chains 2 short light chains Constant region of each protein is similar Variable region of each protein is diverse Antigen binding sites -where antigen is held Idiotypes sites in direct contact with antigen TERM 67
Severe Combined Immuno-Deficiency
DEFINITION 67 Most common form: X-linked affect mostly boys Other forms autosomal recessive inheritance linked to a deficiency of the enzyme adenosine deaminase (ADA) Occurs in a range of severity; from depressed responseto complete lack of immunity May have T cells but no B cells Severe condition - defects both in T and B cells Gene therapy available and effective, but includes anelevated risk of developing leukemia TERM 68
Transplantation of Organs or Tissues
DEFINITION 68 Transplanted organ has different antigens from recipientEach people has unique marker proteins on the cell membrane Serve as antigens (molecular ID tags) when grafted Encoded by Major Histocompatability Complex (MHC): cluster of 140 genes Important in immune system function and transplants TERM 69
human leukocyte antigen
DEFINITION 69 A set of genes within MHC region: human leukocytes antigen (HLA) Encode class I and II proteins Class I: HLA-A, -B, -C Class II: HLA-DRB, -DQB1 Each HLA gene has many different alleles The combination of these alleles are varied and numerous HLA complex helps the immune system distinguishthe body's own proteins from proteins made byforeign invaders TERM 70
Haplotype
DEFINITION 70 Combination of HLA alleles Extremely polymorphic: Each person has uniquecombination of HLA alleles (haplotype) Used for tissue-typing to determine if tissues of donorand recipient are compatible For successful transplantation, HLA haplotypes ofdonor and recipient should be matched each other
Pig-to-Human Transplants
Xenotransplants causes hyperacute rejection Immediate and massive immune response Destroys transplanted organ within hours To overcome this rejection, researchers create transgenic pigs with human antigens on their cells using recombinant DNA technique Isolate and clone human HLA complex genes inject these genes into fertilized pig eggs (or zygote) resulting transgenic pigs carry human antigens Xenotransplants from genetically engineered pigs tomonkey has been successful TERM 77
Vaccine
DEFINITION 77 Memory cells (B cells) the basis of vaccination against infectious diseases Vaccine contains an inactivated or weakened antigen from disease-causing agent Vaccines have removed the risk but the pathogen remains When vaccine is injected, It causes very mild or no infection It stimulates immune system to produce antibodies andmemory cells against that antigen TERM 78
Blood Types
DEFINITION 78 Defined by antigens on surface of red blood cells Humans > 30 different blood types TERM 79
ABO Blood Type
DEFINITION 79 The ABO blood group system is the most important blood type system in human blood transfusion. Blood types are determined by antigensA antigen > AB antigen > BA and B antigens > ABNo antigen > OThose with type A blood carry A antigen on the surface of red blood cells (RBCs) make antibodies against B antigen (anti- B). Same situation in type B blood. A person who has type AB blood: both A and B antigens are present on the RBCs. Type O blood cells carry no antigen on their surface They cannot receive transfusion from A, B and AB TERM 80
AB blood type
DEFINITION 80 universal recipients make no antibodies against the A or B blood they can receive a transfusion from any type of blood
O blood type individuals
universal donors have no antigen on their blood cells they can donate blood to anyone without rejection TERM 82
Transfusion Reaction
DEFINITION 82 ABO antigens of donor and recipient must matchIf you receive a blood transfusion not to match with yours; Immune system will make antibodies against donor blood antigen Cause RBC to form clump Clumped blood cells block circulation Reduce O2 delivery Often end up fatal results Clumped blood cells break down Release large amounts of hemoglobin Hemoglobin accumulates in kidneys
cause kidney failure TERM 83
Rh
Factor
DEFINITION 83 Rh blood group has complex organization Rh positive (Rh+) carries Rh (D) antigen Rh negative (Rh-) does not carry antigenDuring pregnancy or childbirth, small number of fetal cells may cross placenta and enter mothers bloodstream. If mother is Rh- and father is Rh+, fetus could be Rh+. Rh+ fetal blood cells stimulate Rh- mother to produce antibodies against Rh+ antigen. If it is the first pregnancy,this situation will usually not harm either the fetus or mother.During the second Rh+ pregnancy, mothers antibodies cross placenta at the last stage of pregnancy destroy the fetus red blood cells (Hemolysis) TERM 84
RhoGAM
DEFINITION 84 To prevent HDN, Rh- women need to be given RhoGAM (Rh+ antibodies) during the 1st pregnancy RhoGAM antibodies remove Rh- fetal cells from mothers circulation Must be given before mothers immune system produces antibodies against Rh+ antigen TERM 85
AIDS
DEFINITION 85 (acquired immunodeficiency syndrome): a clinical disease that develops after infected with human immunodeficiency virus (HIV) HIV infects and kills T4 helper cells T4 helper cells: important for the onset of immune reaction recognize antigens such as foreign bacteria or viruses activate production of antibodies by B cells HIV infection disables immune system AIDS develops inflammation and tumor at many tissues AIDS causes death from infectious diseases
