Heredity Ch 1 PDF

1/5/25 Chapter 1 Introduction to...

1/5/25 Chapter 1 Introduction to Genetics Laurence Wong Burman University 1 2 Chapter Outline What is Heredity/Genetics? 1.1 Genetics Has a Rich and Interesting History 1.2 Genetics Progressed from Mendel to DNA in Less Looks at traits that can be passed on to offspring Than a Century from parents. 1.3 Discovery of the Double Helix Launches the Era Generally, offspring look like parents, and they do of Molecular Genetics so because parents pass on traits in the form of 1.4 Development of Recombinant D N A Technology genes (set of instructions that determine how an Began the Era of Cloning ↳organism should look like).. 1.5 The Impact of Biotechnology Is Continually Expanding in the twenty-firstproteins Enformation that makes Genetics century is built on a rich 1.6 Genomics, Proteomics, and Bioinformatics Are New tradition of discovery and experimentation and Expanding Fields stretching from the ancient world through the 1.7 Genetic Studies Rely on the Use of Model Organisms nineteenth century to the present day. 1.8 We Live in the Age of Genetics 3 1953-DNA 1st Identified 4. Parental Fetsiblings History of Genetics Between 8000 – 1000 BC – Horses, camels, oxen and wolves were 1.1 Genetics Has a Rich and domesticated with their soon selective Interesting History breeding of these species (i.e., from archeological evidence). – Cultivation of plants, e.g., maize, wheat, rice, etc, began ~5000 BC. – Artificial selection of genetic variants from wild population ( bettercropa 5 6 1  1/5/25 Greek Scholars 1600–1850: The Dawn of Modern Biology Ceredity in Humans) Hippocratic school of medicine (500-400 BC) and William Harvey: Theory of epigenesis (1600) Aristotle (384-322 BC) discussed heredity as it relates to - Structures such as body organs are not initially humans. body fluilds. present in the early embryo but are formed later. Hippocrates (On the seed) argued that active ‘humors’ in - various parts of the body served as bearers of hereditary - States that an organism develops from the traits. Humors drawn from various parts of the male body fertilized egg by a succession of developmental can be passed on to offspring. Humors could be modified events that eventually transform the egg into an and passed on explained how newborns inherited traits that +structure Lot initially by develop Later]. parents acquired in response to the environment. adult. Aristotle proposed that male E semen contained a vital heat This theory conflicted with the Theory of with the capacity to produce offspring of the same form as Preformation that was popular at that time. the parent. He believed that this heat cooked and shaped the menstrual blood produced by the female, which gave - - The fertilized egg contains a complete miniature rise to the offspring. adult called a homunculus (F1.1) 7 8 fetilized egge copied human character ] 1600–1850: The Dawn of Modern Biology The Origin of Species 1859, Darwin published his ideas on the theory of Schleiden and Schwann: The cell theory (1830) evolution in The Origin of Species - All organisms are composed of basic structural 1. Descent with modification units called cells. - Existing species arose from other ancestral species. Louis Pasteur disproved Spontaneous 2. Natural selection Generation - The mechanism for evolutionary change (driven by competition between individuals). - The creation of living organisms from (strong will survive). nonliving components. Theory of evolution (avolution) - Independently proposed by Alfred Russel Wallace In order to have well there should be (environment was the driving force for change). - Darwin however lacked the understanding of the 9 preid al 10 ↳ genetic basis of variation and inheritance. Variation of Inheritance 1.2 Genetics Progressed from 1866: Mendel publishes his findings Mendel to DNA in Less Than a Mendel worked with peas and used quantitative data to support his ideas Century - Traits are passed from generation to generation - Transmission of genetic information from 1850s, Mendel an Augustinian monk who parents to offspring through his experiments birthed the science * His work forms the foundation for genetics: of inheritance at the monastery garden. Defined as the branch of biology concerned with the study of heredity and variation. good things 11 12 -Mendel with recording. counted. > peas - - Data. 2  1/5/25 Mitosis and Meiosis Mendel Mitosis - gth- cells Mendel conducted his experiments before the structure and role of chromosomes were known. - Chromosomes are copied and distributed to daughter cells. 20yrs after his work, researchers through advances - The two resulting daughter cells each receive a in microscopy were able to identify chromosomes. diploid set (2n). 2 diploid. These researchers produced the chromosome theory same parents 7-the. as Meiosis of inheritance thereby uniting Mendel and Meiosis. - Chromosomes are copied and distributed to Walter Sutton and Theodor Boveri independently ↓ gametes. noted that the behavior of chromosomes during - Resulting cells receive only half the number of meiosis is identical to the behavior of genes during chromosomes and are haploid (n). gamete formation described by Mendel. 13 disturbed to 14 agetes gametes. Diploid number (2n) Human Male Karyotype (F1.3) Most eukaryotes have a characteristic number of chromosomes - Called diploid number (2n) Chromosomes in diploid cells exist in pairs - Called homologous chromosomes The chromosome complement of a cell is called the karyotype. ↳defined no. ychram in e set 15 16 Chromosomal Theory of Alleles—The Source of Genetic Inheritance Variation Inherited traits are controlled by genes Alleles residing on chromosomes. - Mutations produce alleles of a gene Genes are transmitted through - The source of genetic variation (white gametes eye mutation in Drosophila; F1.6) - Maintains genetic continuity from Genotype generation to generation. - The set of alleles for a given trait Chromosomes can contain hundreds of Phenotype genes (e.g., D. melanogaster - Expression of the genotype Chromosome 1; F1.5). - Produces an observable trait or phenotype 17 18 3  1/5/25 [Not protein bt genes info] chromosomes carry DNA is the Carrier of Genetic Information Work on white eyed Drosophila showed that the mutant trait 1.3 Discovery of the Double could be traced to a single chromosome, confirming the idea Helix Launched the Era of that genes are carried on chromosomes. Once that was established, investigators turned their Molecular Genetics attention to identifying which chemical component of chromosomes carries genetic information. Once it was accepted that DNA carries genetic info, Not protein efforts were focused on deciphering the structure of Research of Avery, MacLeod, and McCarty the DNA molecule and the mechanism by which info - In 1944, published experiments showing DNA was is stored in it to produce a phenotype. carrier of genetic information in bacteria. 19 20 Structure x *** Structure of DNA of DNA Monomer is - Nucleotide consisting of a sugar (deoxyribose) Atizneutolypes. 1953, James Watson and Francis Crick - Bonded to a phosphate - Also bonded to the bases adenine (A), DNA is (F1.7) cytosine (C), guanine (G), and thymine (T) - Antiparallel (5’ to 3’, 3’ to 5’) goione ng Nucleotides form A=T and G≡C (hydrogen band) &S eachstand - Double-stranded helix complementary base pairs between strands - Made of nucleotides (F1.7). 21 22 Structure of RNA RNA is like DNA, except that - It is usually single-stranded & rwn Sugartouted (some can form double panster M stranded sections if the bases biger are complementary, e.g., tRNA) - It has - uracil (U) in place of thymine (T) - The sugar in RNA Q nucleotides is # of deoxyribose ribose instead is 23 Scale 24 4  1/5/25 The Central aplicat DNA is transcribed into several types of RNA non are 4951 BRNA Dogma of Biology · 1. Ribosomal RNA (rRNA) are structural components of ribosomes (used with protein eapyFo.. - -- DNA → RNA → Protein - > synthesis). These are the most abundant RNA. ve - DNA is transcribed to 2. Messenger RNA (mRNA) are the nucleic acids in RNA O that carry information from DNA to ribosomes. RNA is translated into These are transient molecules. [provi mag to proteins -usdit protein (F1.8) 3. Transfer RNA (tRNA) are adapter molecules that translate the language of nucleic acids to amino acid sequence. 25 26 The Genetic Code Proteins mRNA carries the genetic Proteins are the end-product of gene expression. information from the DNA in Protein function/action or location in a cell produces the nucleus to the ribosomes phenotype(s).. in the cytoplasm to be decoded to proteins. - e.g., Enzymes are proteins Diversity of proteins are created by numerousdiff combinations Each triplet nucleotide combinations of 20 -- different amino acids. sequence, called the codon, A single-nucleotide change in the DNA can lead to an specifies a specific amino altered mRNA codon and the insertion of a different amino acid. acid into a growing protein chain. ↓ - e.g., sickle-cell anemia is a result of a- E single mutation leading to an altered version of the Codons form the genetic triplet/codonsa hemoglobin protein. [ros code. representcertain 27 28 DNA mutation results in an altered Hemoglobin is the protein that transports oxygen hemoglobin that causes Sickle Cell Anemia from the lungs to cells in the body. (F1.9). ⑪ Figure 1–10 Normal red blood cells (round) and sickled red blood cells. © 2015 Pearson Education, Inc. 29 30 5  1/5/25 ⑧ Recombinant DNA Technology 1.4 Development of Two important discoveries in the 1970’s: ZEnzyme. Recombinant DNA Technology 1. Restriction endonucleases – - “scissors” that cut DNA at specific Began the Era of Cloning sites, producing a reproducible set of fragment. 2. DNA ligase – enzymatically joins 2 DNA fragments together. - "cut and splice" or recombine DNA, hence, the birth of-recombinant DNA technology. Fat paste and 31 32 ①many DNA Cloning copies of DNA. Restriction enzymes and DNA * ligase allow the DNA cloning permits researchers to prepare splicing of DNA enidest large numbers of identical DNA molecules. fragments into A variety of techniques, often referred to > - cloning vectors. - recombinant DNA technology, are used in Collections of clones of complete DNA cloning. genomes have been Recombinant DNA is simply any DNA created (i.e., molecule composed of sequences derived from genomic libraries). different sources. 33 34 permit Biotechnology is now used in: Health care, e.g., in diagnosis using genetic 1.5 The Impact of Biotechnology testing is Continually Expanding Supermarket products Agriculture, e.g., breeding/cloning, transgenic plants Court system. e.g., paternity, criminology and forensic testing 35 36 6  1/5/25 Some Genes Whose Mutant Forms Biotechnology in Genetics and Cause Human Disease (F1.12) Medicine The molecular basis for hundreds of genetic disorders is now known. - Many of these genes have been mapped, isolated, and cloned. Biotechnology-derived genetic testing: - Utilized in prenatal diagnosis - Tests for heritable disorders 37 38 Biotechnology Used in Agriculture Biotechnology has been used for the genetic 1.6 Genomics, Proteomics, modification of crop plants for - GMOs, e.g., increased herbicide, insect, and and Bioinformatics are New viral resistance and Expanding Fields - Nutritional enhancement - Water use reduction (less water) - Freeze tolerance Cloning of livestock (e.g., Dolly, F.11) - Somaticcl/E a y 39 40 Genomics, Proteomics, and Common Origin Bioinformatics Genomics All life has a common - Studies the structure, function, and evolution of origin. genes and genomes Genes with similar Proteomics (not protein made cells) all are in functions in different - Identifies a set of proteins present in cells under organisms are similar in a given set of conditions structure and in DNA - Studies their functions and interactions sequence. * Same components bt diff variations. Bioinformatics * Mankey / Human. - Uses computer hardware and software for processing/analysing nucleotide and protein data 41 ↳ comparin genes among differ species 42 7  1/5/25 Ways to study Genel Modern Approaches to Understanding Gene Function Classical or forward genetics - Identifying the genes that caused mutant phenotypes Reverse genetics - DNA sequence of a particular gene of interest is known, but its function is not* done it and see and study. so we Gene - knockout -& Allows scientists to render genes nonfunctional to investigate the possible role of that gene > Remove and what to animal see happen -. 43 44 Model Organisms Used to Study Human Diseases Model organisms for genetic study meet these 1.7 Genetic Studies Rely on the criteria: - Easy to grow Use of Model Organisms - - Short life cycle (grow week within that so we work can fastly) · - Produce many offspring - Genetic analysis is straightforward (crosses x). It became clear that genetic mechanisms were similar in most organisms. Recombinant DNA technology gives the ability to transfer genes across species. 45 46 Table 1.1 Model Organism: Historical First generation of model organisms: (F1.13) Iflatwarm) (mice) 47 48 8  1/5/25 Model organisms to understand Model Organism: Modern Clean org) * No Ethical unsent needed · humans. E Much of what scientists learn by studying the genetics of model organisms can therefore be applied to humans as the basis for understanding and treating human diseases. In addition, the ability to create transgenic Microbes: (F1.14) - organisms by transferring genes between species - - Viruses: T phages and lambda phages has enabled scientists to develop models of human ( - Bacteria: Escherichia coli diseases in organisms ranging from bacteria to - Yeast: Saccharomyces cerevisiae (Bst colgles) enkar fungi, plants, and animals transfer to another changes)] > taking (See one species gene from. 49 50 The Age of Genetics -1865: Mendel set the stage for the study of genetics 1.8 We Live in the Age of Genetics rapidly developed from Mendel’s peas to Genetics the Human Genome Project 1962: Nobel Prize awarded to Watson, Crick, and Wilkins - Numerous Nobel Prizes have been awarded since then in the field of genetics 51 52 Recent and Famous Anot. sequence Human Genome Project Dr. Venter Human genome # Inventor of “Shotgun Sequencing”.break - into more ↳1 epref DNA and pieces. = - = 53 54 9  1/5/25 Cost of Human Genome Project In 1990, the US Congress established funding for the Human Genome Project and set a target completion date of 2005. Although estimates suggested that the project would cost a total of $3 billion over this period, the project ended up - costing less than expected, about $2.7 billion dollars. Additionally, the project was completed more than two years ahead of schedule (2003). It is also important to consider that the Human Genome Project will likely pay for itself many times over if one considers that genome-based research will play an important role in seeding biotechnology and drug development industries, not to mention improvements in human health. &t new Drugs technol & Impro , 3 in [compile] Health. 55 Human 56 The Age of Genetics (F1.15) I > - soo 57 58 Future of Genetics Genetics and its applications in biotechnology are developing much faster than the social conventions, public policies, and laws required to regulate its use. Society is faced with a host of sensitive genetics- related issues: - Prenatal testing - Ownership of genes - Access to/safety of gene therapy - Genetic privacy - Ethics of gene manipulation 59 60 10 What is Genetics? Genetics is the study of how parents pass traits to their children. These traits are decided by genes, which are like tiny instructions in your cells. For example, your genes decide your eye color or height. History of Genetics (Slide 1.1) 1. Ancient Times People started domesticating animals (like dogs and horses) and growing crops like wheat and rice thousands of years ago. They chose the best ones to breed, which is called selective breeding. 2. Greek Theories Hippocrates: Believed body uids carried traits. Aristotle: Thought male semen had “heat” that shaped the baby inside the mother. 3. Modern Biology (1600–1800) William Harvey: Discovered embryos grow step by step, not all at once. Cell Theory: All living things are made of tiny building blocks called cells. Louis Pasteur: Proved that living things don’t just appear from nowhere (no “spontaneous generation”). 4. Darwin’s Evolution Charles Darwin: Explained how species change over time through “natural selection.” But he didn’t know how traits were passed down. Mendel and Inheritance (Slide 1.2) 1. Gregor Mendel’s Peas (1860s) Mendel experimented with pea plants to discover how traits like color and size are passed. He found that some traits are dominant (strong) and others are recessive (weaker). His work laid the foundation for understanding inheritance. 2. Chromosomes and Genes In the early 1900s, scientists discovered that chromosomes (tiny structures in cells) carry genes, which decide traits. DNA and Molecular Genetics (Slide 1.3) 1. DNA is the Blueprint Scientists later found that DNA (a molecule in cells) carries all the instructions for making living things. Watson and Crick (1953): Discovered DNA looks like a twisted ladder (double helix). 2. How DNA Works DNA has four chemical “letters” (A, T, G, C) that pair up (A with T, G with C). fl. DNA makes RNA, and RNA helps make proteins. Proteins create traits like hair color. 3. Central Dogma The process: DNA → RNA → Protein. Recombinant DNA and Biotechnology (Slides 1.4 and 1.5) 1. Recombinant DNA Scientists can now cut and join pieces of DNA to change how genes work. This is called recombinant DNA technology. It’s used to make genetically modi ed organisms (GMOs) or create medicines. 2. Examples of Biotechnology Medicine: Testing for genetic diseases. Agriculture: Creating plants that resist pests or need less water. Crime-solving: Using DNA to catch criminals. New Fields in Genetics (Slide 1.6) 1. Genomics: Studies all the genes in an organism. 2. Proteomics: Studies proteins that genes create and how they work. 3. Bioinformatics: Uses computers to analyze genetic data. Model Organisms (Slide 1.7) 1. Why Use Model Organisms? Scientists study animals like fruit ies, mice, or bacteria because they grow fast, have short lifespans, and share many genes with humans. These studies help us understand human diseases and genetics. Human Genome Project (Slide 1.8) 1. Mapping Human Genes In 2003, scientists completed the Human Genome Project, which mapped all the genes in humans. This helps doctors understand diseases and create treatments. 2. Future Challenges Ethical questions: Should we be allowed to edit genes? Who owns genetic information? Important Terms You Should Know 1. Gene: A piece of DNA that controls a trait (like eye color). 2. Chromosome: Structures in cells that carry genes. 3. DNA: The molecule that stores genetic instructions. 4. Mutation: A change in DNA that can lead to new traits or diseases. fl fi 5. Dominant and Recessive Traits: Strong traits vs. hidden traits. 6. Central Dogma: DNA → RNA → Protein. 7. Biotechnology: Using genetics in medicine, farming, or research. 8. Model Organism: Small animals used to study genetics (e.g., fruit ies). 9. Human Genome Project: Mapped all human genes.