Human Genetics Fall 09 Dr Grafton Exam 1 Outline of Chapters A Ch 1 1 Genetics Is the study of inherited variation and traits Genes are the units of heredity Genes are composed of Deoxyribonucleic Acid DNA Traits are produced by an interaction between the genes and the environment 2 Genes protein 3 Alleles are variants of genes The blueprints A section of DNA that contain the instructions for the production of a They form by Mutation Mutations in sperm or egg cells are passed on to the next generation May be positive neg or neutral But often Negative 4 The Genome Is the complete set of genetic info For an organism i Includes All of the genes present in an organism and other DNA sequences that do not encode genes Proteomics Which genes are expressed in cell types Only 1 5 of the DNA in the human genome encodes protein Rest includes highly repeated sequences with unknown functions Includes about 24 000 protein encoding genes Cataloged in database Mendelian inheritance in Man MIM 5 Levels of genetics Chromosome DNA Gene Human Genome 23 chromosome pairs Individual Family Population 6 Deoxyribonucleic Acid DNA A double stranded polymer consisting of a chain of nucleotides Deoxyribonucleotide Components Phosphate Sugar Deoxyribose Base Guanine G Thymine T Adenine A Cytosine C protein 7 Ribonucleic Acid RNA Single stranded polymer of ribonucleotides Ribonucleotides components i Phosphate ii Sugar Ribose iii Bases G C U A Several types Uses info on DNA to construct The sequence of the bases code for the amino acid sequence in a 8 Replication DNA Transcription RNA Nucleus Translation Protein Cytoplasm 9 Variation Polymorphisms population Are variations in the DNA sequence that occur in at least 1 of the Single nucletide polymorphisms SNPs are single base sites that differ among indiviuals and are important as markers 10 Chromosomes Composed of DNA and protein histones Found in the nucleus of the cell Human cells have 46 chromosome The sex chromosome X and Y 22 pairs of autosomes Females XX Males XY 11 Karyotype 12 Cells Whole set of 23 chromosomes All cells with a nucleus in the body contain the same genetic info Differentiation conrolled by variation in gene expression Stem cells are less specialized and can become many diff cell types causes cells to differ in appearance and function This is 13 Levels of Organization Atom Molecule Macromolecule Organelle Cell Tissue Organ Organ system Organism 14 The Individual The genotype of an individual is the alleles they carry The Phenotype is the visible trait Dominant alleles are expressed if the individual carries one or two Recessive alleles are only expressed if the individual carries two copies of the allele copies of the allele 15 The Family 16 Population Inheritance of traits can be observed in families A pedigree indicates the structure of a family schematically Is a group of interbreeding individuals The gene pool is the alleles in a population Evolution is the changing allelic frequencies in pop Over time 17 Evolution 98 of human DNA sequences are shared w chimps 18 Most Genes do not function alone Mendelian traits are determined by a single gene Most traits are multifactorial and not controlled by a single gene They are influenced by more than one gene and the environment Some illnesses may occur in diff forms Mendelian multifactorial and non inherited 19 Genes and disease risk Mendelian traits have simple inheritance Multifactorial traits more complicated i BRCA1 gene and breast cancer Ethnic influences as well as environmental B Ch 2 Cells mitosis 1 Cells Somatic Germ 2 Somatic cells 3 basic parts Muscle and Nerve cells Reproductive sperm and egg i Cell membrane ii Nucleus iii Cytoplasm water and organelles Nucleus i Memebrane nuclear enevelope and nuclear pores Protein shape determines the function of that protein 3 Golgi apparatus Lysosomes Peroxisomes 4 Mitchondria break apart things deal with things coming into the cell Powerplant of cell Turns glucose into ATP energy for cell Have outer membrane and inner membrane with wrinkles called Cristae 5 Phospholipids Hydrophillic head likes water Hydrophobic tail hates water Diagram Embedded into the phospholipid bilayer i Function Letting stuff in out of cell receptors transporters 6 Proteins 7 Cytoskeleton 8 Cell Cycle Interphase Microfilaments Microtubules Tubulin dimer give shape Intermediate filaments G1 phase Manufacturing product S Phase DNA replication G2 Phase same as G1 Mitosis cell division in Somatic cells Prophase DNA is condensed into chromosomes spindle assembles centrioles appear and nuclear envelope begins to degrade Metaphase Chromosomes align in the middle Anaphase Centromeres pull separate sister chromatids from each other Telophase cell begins to divide into two spindle disassembles and nuclear envelope re forms Cytokinesis Between G1 S phase stand by G0 phase the cell can either proceed to division or cell death Apoptosis or remain specialized till told 9 Chromatid Chromosome is a pair of sister chromatids 1 side of chromosome Chromatid 10 Centromere center of chromosome 11 Checkpoints DNA damage inhibits cell till damage is fixed Apoptosis If survivin accumulates mitosis will resume Spindle assembly is spindle built Are chromosomes attach aligned in middle Too damaged Apoptosis occurs Cell death 12 Mitotic clock cell life span i Telomeres at ends of chromosome s 100 s to 1 000 s of bases long ii Loses some bases every time cell divides 13 Apoptosis programmed cell death Protein death receptors which trigger and activate killer enzymes caspases i Trigger degrading of cytoskeleton and so on Blebs Bits of cell fragments toward end of death Phagocytes engulf these fragments 14 Signal transduction Stimulus light chemical temp toxin hormone and growth factor attach to receptor protein 15 Stem Cell Diagram need to know totipotent Pluripotent C Ch 3 Meiosis 1 Mitosis 2 daughter cells genetically identical same of chromosomes in daughter cell 2n One division Occurs in somatic cells most cells Occurs throughout life cycle Used for growth repair asexual reproduction 2 Meiosis Four daughter cells Two divisions Genetically diff Only in germline cells After sexual maturity Sexual reproduction 3 Meiosis Diagram Chromosome of daughter cells half that of parent cell 1n Early Prophase homologs pairs chromosome that have been Prophase 1 i Genetic variation copied Metaphase 1 Late Phase Chromosome condense i Homologs align along center of cell ii Crossing over Diagram Anaphase 1 i