...Chapter 14 Mendel and the Gene Idea Lecture Outline Overview • Every day we observe heritable variations (such as brown, green, or blue eyes) among individuals in a population. • These traits are transmitted from parents to offspring. • One possible explanation for heredity is a “blending” hypothesis. ° This hypothesis proposes that genetic material contributed by each parent mixes in a manner analogous to the way blue and yellow paints blend to make green. ° With blending inheritance, a freely mating population will eventually give rise to a uniform population of individuals. ° Everyday observations and the results of breeding experiments tell us that heritable traits do not blend to become uniform. • An alternative model, “particulate” inheritance, proposes that parents pass on discrete heritable units, genes, that retain their separate identities in offspring. ° Genes can be sorted and passed on, generation after generation, in undiluted form. • Modern genetics began in an abbey garden, where a monk named Gregor Mendel documented a particulate mechanism of inheritance. A. Gregor Mendel’s Discoveries 1. Mendel brought an experimental and quantitative approach to genetics. • Mendel discovered the basic principles of heredity by breeding garden peas in carefully planned experiments. • Mendel grew up on a small farm in what is today the Czech Republic. • In 1843, Mendel entered an Augustinian monastery. • He...
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...Mendel on Patterns of Inheritance Gregor Mendel, a monk, well read in natural sciences (Pruitt & Underwood, 2006, p. 64), wanted to answer the unanswered questions that stemmed from Darwin’s theory about heredity. He chose to study the pea plant to gain knowledge about how heredity works. Mendel’s success is contributed to the way he chose to conduct his experiments. Mendel decided to keep his control group small, unlike many of his colleagues, focusing on only seven traits. He kept excellent records of all of the results of the experiments and his choice to study the pea plant, “an organism that can be easily manipulated in breeding experiments” (Pruitt & Underwood, 2006, p. 64) proved to be a good move. Mendel also used “mathematical analysis” (Pruitt & Underwood, 2006, p. 64), an uncommon approach in his day, for showing results of the experiments. A few of Mendel’s discovered six major principles about heredity from his research. An example of one of his principles states that for every gene there are two factors or alleles, “the different forms a gene might take” (Pruitt & Underwood, 2006, p. 68). If an organism has two alike alleles for a specific trait the organism is considered homozygous for that trait; homo meaning the same. On the flip side, if an organism has two alleles that are different then the organism is considered heterozygous for that trait; hetero meaning different (Pruitt...
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...somatic cell- all the diploid body cells of an animal that are not involved in a gamete formation. gametic cell- a cell that fuses with another cell during fertilization in organisms that reproduce sexually, homologous chromosome , sister chromatid, karyotype, autosome and sex chromosome. How many chromosomes are in a human somatic cell? 46 How many homologous chromosome pairs are in a human somatic cell? 22 How many chromosomes are in a human gamete? 23 How many homologous chromosome pairs are in a human gamete (trick question)? 46 Which stage of the human life cycle is diploid (2n)? Which is haploid (n)? Which processes form the transition from haploid to diploid and diploid to haploid? Meiosis- The goal of meiosis is to produce four haploid gametes from one diploid somatic cell. This occurs through two cell divisions: meiosis I and meiosis II. Interphase - as in mitosis, the DNA content of the cell doubles from 2n to 4n. Meiosis I- Prophase I. DNA supercoils, tetrads form and crossing over occurs between maternal and paternal homologous chromosomes. Metaphase I. Homologous chromosome pairs line up along the equator of the cell in stacks instead of end to end. The random alignment of the homologous chromosomes during metaphase I is known as independent assortment. Anaphase I. Homologous chromosome pairs separate toward opposite poles of the cell. Nondisjunction can occur at this stage. Telophase I/cytokinesis. Nuclei reform in each of the two daughter cells as the mother cell...
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...Structure of DNA DNA Structure and replication can be described as the molecule of inheritance. There are many complex issues to its structure and forms of inheritance. One scientist researched the structure of DNA at a time during the 19th century when there was no knowledge of DNA’s role in heredity. By the 1950s a series of discoveries convinced the scientific community that DNA acts as the hereditary material. To describe DNA would be like a blueprint found in every cell in all living organism. Living organisms are made of cells. Every cell has a nucleus, and chromosomes. Human beings have 46 chromosomes that are paired into 23 chromosomes that contain hundreds of genes. The genes contain the formula for proteins that make most of the body. The structural proteins form various essential parts of the body such as skin, hair, and muscle. These chromosomes can be described as a twisted ladder held together by a backbone that is made up of sugar phosphate. Long coils of DNA (Deoxyribonucleic Acid) store all the information that the body needs such as the physical features of how one will look and their everyday functions. The DNA is a thread formed by two strands, twisted together to form a Double Helix. The Double Helix looks like...
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...other nucleotide sequences. Gregor Mendel -An Austrian monk who gained posthumous fame as the founder of the new science of genetics. Genetics -The branch of biology that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms. Deoxyribonucleic acid (DNA) is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Ribonucleic acid (RNA) Is a ubiquitous family of large biological molecules that perform multiple vital roles in the coding, decoding, regulation, and expression of genes. Nucleotides -are organic molecules that serve as the monomers, or subunits, of acids like DNA and RNA. Mendel's research was with plants, the basic underlying principles of heredity that he discovered also apply to people and other animals because the mechanisms of heredity are essentially the same for all complex life forms. Heredity -is the passing of traits to offspring from its parents or ancestor. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve. With all of the seven pea plant traits that Mendel examined, one form appeared dominant over...
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...Analysis/Discussion: Mendel had three different laws to describe genetics which were The Law of Segregation, The Law of Independent Assortment, and The Law of Dominance. Law of Dominance - The law of dominates states that one factor for a trait will be dominant, and the other will turn out to be recessive. As an Example, if a hybrid red fly (Rr) crossed with a pure white fly (rr), the results (50% Rr, and 50% rr) would carry the white gene (r). Though only 50% of fruit fly would show it cause of the dominance of the red trait (R). Law of Segregation - This sates that two alleles for a trait are split half and half into the gametes, which give the offspring an equal chance of getting either one. An example, in all of the punter squares that each fly was given the chance to have each trait, even though a couple may not have been shown. A red fly has an equal possibility to be red as thew other fly. Law of Independence - This law states that alleles for different traits are passed on independently. This means that each gene (alleles) combination is likely to occur. As an example, each offspring get one gene from each...
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...Chromosomes are thread like gene carrying structures found in the nucleus. Each chromosome consists of one DNA molecule and associated proteins (ghr.nlm.nih.gov). Genes are segments of DNA. These are the units which make up chromosomes, responsible for the inheritance of specific characteristics. Alleles are alternate versions of genes. A dominant allele is the version of that gene that is always shown as the characteristic. A recessive allele is only shown if there is no dominant allele present inherited information is passed on in the form of each genes specific sequence of nucleotides that make up DNA. Most genes programme cells to synthesise proteins that produces an organisms inherited traits. Traits are organisms’ characteristics. The transmission of hereditary traits is based on the replication of DNA which produces copies of genes that can be passed on from parents to offspring. Humans have 46 chromosomes in almost all cells (apart from sex cells for example sperm and egg cells which are haploid or have half the number of chromosomes) Sexual reproduction results in greater degree of variation. Two parents give rise to offspring that have unique combinations of genes inherited from two parents. Sexual reproduction generates genetic variation by homologous parings (half of the chromosomes form the mother and half from the father). The process crossing over is the exchange of genetic material which enhances variation in a species; it produces recombinant chromosomes...
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...MENDELIAN GENETICS DEFINITION OF TERMS * Genetics – the study of heredity and variation * Heredity – the transmission of traits from one generation to another, from parents to offspring; the protoplasmic continuity between parents and offspring * Variation – any difference existing between individuals of the same species * Chromosome – rod-shaped body in the nucleus of eukaryotes and prokaryotes that contains the hereditary units or genes seen particularly during cell division * Gene – the unit or heredity occupying a particular location on the chromosome and passed on to offspring * Locus – the location of a gene on a chromosome * Diploid – the 2N number of chromosomes; twice the number of chromosomes found in gametes * Haploid – the N number of chromosomes; half the diploid number; the number characteristic of gametes that contain only one set of chromosomes * F1 generation – first filial generation; the first-generation offspring of a genetic cross that has at least two generation * F2 generation – second filial generation; the second-generation offspring of a genetic cross * Homozygous – a pair of similar of like genes for any one character * Heterozygous – a pair of contrasting traits of two kinds of genes * Genotype – the particular genes of an individual that determine a specific trait * Phenotype – the outward appearance of an organism, caused by genetic and environmental influences * Allele –...
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...Chapter 15 Overview: Locating Genes Along Chromosomes * Mendel’s “hereditary factors” were genes * Today we can show that genes are located on chromosomes * The location of a particular gene can be seen by tagging isolated chromosomes with a fluorescent dye that highlights the gene Mendelian inheritance has its physical basis in the behavior of chromosomes * Mitosis and meiosis were first described in the late 1800s * The chromosome theory of inheritance states: * Mendelian genes have specific loci (positions) on chromosomes * Chromosomes undergo segregation and independent assortment * The behavior of chromosomes during meiosis can account for Mendel’s laws of segregation and independent assortment * Morgan’s Experimental Evidence: Scientific Inquiry * The first solid evidence associating a specific gene with a specific chromosome came from Thomas Hunt Morgan, an embryologist * Morgan’s experiments with fruit flies provided convincing evidence that chromosomes are the location of Mendel’s heritable factors Morgan’s Choice of Experimental Organism * Several characteristics make fruit flies a convenient organism for genetic studies * They produce many offspring * A generation can be bred every two weeks * They have only four pairs of chromosomes * Morgan noted wild type, or normal, phenotypes that were common in the fly populations * Traits alternative to the wild type are called mutant phenotypes Correlating...
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...Mendel’s “First Law”: Observing Anthocyanin in Brassica rapa Abstract The foundation of genetics lies with the principles that Gregor Mendel outlined after his experiments with pea plants where he discovered the relationship between physical characteristics, or phenotype, and genetic traits, or genotype. This experiment aimed to reproduce Mendel’s results with the Brassica rapa plant, noted for it’s fast generation time, and anthocyanin, a purple pigment that can be visually tracked through subsequent generations. It is important for experiments resulting in scientific discovery to be replicable and peer reviewed. Since Mendelian genetics are the foundation of scientific education, including answering questions about evolution and heredity of beneficial or fatal genes, his experiment is a valid and important choice. The hypothesis was that the presence of anthocyanin in Brassica rapa follows Mendel’s laws. By germinating the P1 generation and creating the F1 and F2 generations through pollination the hypothesis was tested. The experimental hypothesis was accepted with ------ error and the null hypothesis that these results were due to chance was rejected. Introduction A phenotype provides a clear visual cue for examining the inheritance pattern of genotypes and whether or not these patterns follow Mendelian genetic principles. Gregor Mendel is someone who is often referred to as the “father of genetics,” and discovered important theory pertaining to heredity. He did this...
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...study of humankind in all time and places * Anthropology is: 1. A Social Science * Academic discipline concerned with society and the relationships among individuals within a society, which often reply primarily on empirical approaches 2. Studies Culture * Culture is composed of ideas, values and perceptions * Culture is not instinctual, it must be learned and shared * Culture only exists within a society or group of people * Culture is a human adaptation to their environment 3. Holistic * The various parts of human culture and biology must be viewed in the broadest possible context in order to understand their interconnections and interdependence * Cultural Anthropology * The study of patterns of human behavior, thought and emotions, focusing on humans as culture-producing and culture-reproducing creatures * Ethnography * Detailed description of a particular culture * Ethnology * Study and analysis of different cultures from a comparative or historical point of view * Linguistic Anthropology * The study of human language – looking at their structure, history, and relation to social and cultural contexts * Descriptive Linguistic * Recording,...
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...In the 19th century Gregor Mendel started to recognize inheritances or traits passed from parents to offspring in a very consistent pattern. Thanks to new technology in the 1940s and the 1950s like higher powered microscopes scientists could see what they could never see before. They discovered chromosomes and found that they were made out of something called DNA as well as proteins. Further experiments led them to realize that DNA held the code of life. Soon enough scientists started asking what DNA was made of and why it is so important. What they discovered was that DNA consists of four nitrogenous bases called adenine, thymine, cytosine, and guanine. Scientists still wanted to learn how all living things in this world could be created by...
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...originated in the mid-19th century when Gregor Mendel discovered over a ten year period of experimenting with pea plants that certain traits are inherited. His discoveries provided the foundation for the science of genetics. Mendel's findings continue to spur the work and hopes of scientists to uncover the mystery behind how our genes work and what they can reveal to us about the possibility of having certain diseases and conditions. The scientific field of genetics can help families affected by genetic disorders to have a better understanding about heredity, what causes various genetic disorders to occur, and what possible prevention strategies can be used to decrease the incidence of genetic disorders (Pitman, 2002). What is Heredity? Why do children look like their parents? Why do brothers and sisters resemble each other? This is because we “inherent” traits from our parents. The passing of traits from parents to child is the basis of heredity. Traits are physical characteristics. Eye color, nose shape, and many other physical features are some of the traits that are inherited from parents (Kristine & Stewart, 2007). What is genetics? Genetics is the science that studies the mechanics of heredity, or the means by which traits are passed from parents to offspring. Through genetics a number of specific disorders have been identified as being genetically caused (ibid, 2007). Dominant Inheritance Dominant inheritance occurs when one parent has a dominant, disease-causing...
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...signal anticipation of a subsequent food reward. Pavlov called with conditional reflexes, but if now known as classical conditioning or associative learning. -Operant conditioning is a type of learning in which behavior is strengthened if it is reinforced, and weakened if it is punished. Operant conditioning results in behavior modification through positive reinforcement. Skinner’s favorite animal was a pigeon and skinner reasoned that when a hungry pigeon would receive a food reward, it might associate the food with the execution of a particular behavior and would repeat that behavior. 2. What contributions did Lorenz and von Frisch make to understanding social behavior? (Pages 4/5) -Lorenz formulated the idea of fixed action patterns of instinctive behaviors. Such stereotyped behaviors are set in motion by an innate releasing mechanism, which elicits a fixed sequence of behavioral events. (i.e. courtship and mating rituals, nest building for birds, ect) Lorenz also popularized the notion of imprinting, in which animal learns the characteristics of its parents. -Karl von Frisch dedicated much of his life to the study of bees. In doing so, completed experiments that studied both the sensitivity of honeybees to colors, ultraviolet, and polarized light, along with another experiment that discovered how communications might occur, and lastly...
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...Contributions to the Discovery of DNA |Contributor(s) |Contribution | | |Demonstrated and quantified inheritance of traits between generations. 1857, Austria | |Gregor Mendel | | | |Discovered transformation. 1928, bacteriologist trying to develop a vaccine against Streptococcus pneumoniae. Two | |Frederick Griffith |strains, smooth edge (with polysaccharide capsule) and rough (without). S bacteria killed mice, R did not. Dead S | | |bacteria did not. Heat killed S. with the capsule did not. R bacteria mixed with heat-killed S bacteria killed mice. | |Vaccine |Material produced from weakened or killed microorganisms to stimulate an immune response and thereby protect the body | | |against infection. | |Transformation |A change in phenotype when bacterial; cells take up foreign genetic material. | | ...
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