Fundamentals of Genetics Lecture 1 Introduction to Genetics What is Genetics Genetics is the study of traits both inherited and expressed as well as inherited and not expressed Genetics is a science devoted to the study of the underlying basis of heredity and variation Each organism has its own genetic blueprint that makes it different from others Genetic information is stored as DNA Lengths of the DNA code for sets of discrete instructions called genes The existence of genes was first inferred in 1866 by Gregor Mendel What we know Currently the accepted theories of genetics are the germ plasm theory the cell theory and Mendelian inheritance The germ plasm theory is that all cells contain a complete set of genetic information The cell theory is that all life is composed of cells and cells arise only from cells Mendelian inheritance says that traits are inherited in accord with defined principles The Rich History of Genetics Pre Mendel genetics began with the advent of the microscope in 1500 People began to ask where we come from and formulated different theories One of these theories was preformationism where a homunculus was housed inside a sex cell and therefore offspring only received genetic material from one parent Blending inheritance was another theory that hypothesized that there was blending between parental types For example you would get green offspring from yellow and blue parents The rise of cytology the study of cells then began Acquired inheritance is the theory that traits acquired during an organism s lifetime will be transferred to the offspring Pangenesis persisted as a viable hypothesis from the time of the ancient Greeks until the late 1800s In 1833 Brown described the nucleus of the cell Cell theory was proposed by Mathias Jacob Schleiden and Theodor Schwann in 1839 and said that all life is composed of cells Also in 1839 Miescher discovered nuclein in white blood cells In 1856 Darwin published On the Origin of Species but could not explain inheritance The germ plasm theory was proposed by August Weismann and introduced the concept of germ cells or gametes This disproved the theory of acquired characteristics Mendel In 1866 Mendel published experiments on pea plants He also revealed the principles of heredity but was not recognized until 1900 The Rich History of Genetics Serious study of genetics began in 1900 when the work of Mendel was rediscovered Carl Correns Hugo De Vries and Erich von Tschermak were cytologists who were convinced that a physical substance was transmitted from parent cell to progeny cells In 1902 it was noted that chromosome segregation during gamete formation paralleled the behavior of genes Walter Sutton and Theodore Boveri were credited for the chromosome theory of heredity In 1908 Archibald Garrod discovered that changes in genes could lead to changes in enzymes leading to inherited diseases in humans This led to the one gene one enzyme hypothesis In 1923 the inborn errors of metabolism idea was introduced Starting in 1940 studies using microbes began The merger of genetics and biochemistry led to molecular genetics James Watson and Francis Crick with the help of Maurice Wilkins and Rosalind Franklin discovered the 3D structure of DNA in 1953 Gilbert and Sanger developed DNA sequencing in 1977 Kary Mullis introduced PCR in 1983 The availability of whole genome sequences led to the study of all the genes in a genome genomics and of all the proteins coded by a genome proteomics The fusion of genetics with computer science created the field of bioinformatics During the late 1990s and early 2000s a merger of genetics with physicochemical methods like mass spectrometry occurred taking us into a new era Lecture 2 The New Genetics Genetic manipulation has existed for thousands of years Selective breeding of crops developed better strains of wheat Cross pollination of date plants was conducted in 870 B C Genetics Influences Every Aspect of our Lives Genetics influences what we eat For example the green revolution in the 1950s and Norman Borlaug The Green Revolution The green revolution began in the 1950s and increased grain production exponentially with wheat plants It was said to be the first use of genetic techniques to develop new strains of crops It used the germ plasm theory to its advantage Because of the green revolution countries were able to avoid famine It caused the production of high yield varieties of every major crop in the world such as sorghum maize cassava beans wheat and rice Maize production in the U S between 1942 and 2002 changed from 20 bushels ha to 250 bu ha Why do we need to improve what is working There are limited natural resources in this world such as fossil fuel and land Land is being lost to urbanization and topsoil loss Genetics is breeding out the adaptive response Unexpected threats also highlight the need to improve such as plant infections Over Fishing It is estimated that the worldwide demand for food fish will increase to 150 160 million tons by 2030 Genetics has helped to reduce the amount of taking fish from the environment by maintaining diverse stocks and creating GMO fish Genetics Influences Every Aspect of our Lives Genetics also influences our health through disease susceptibility genetic disorders pharmaceuticals development and possibly even intelligence and personality What else can we do with genetics Genetics can also be used in medical research and health behavioral research mating systems natural resources management conservation forensics politics and many many other areas What about species that are difficult to observe Species that are difficult to observe may be nocturnal skittish or their mating may take place out of view Genetics tools and populations Migration affects the movements and geneflow in a population Population size affects the sex ratios Non invasive sampling of a population involves molecular mark recapture Genetics can identify relationships in order to obtain genetic structuring and determine family groups Genetics can discover the life history such as the age of reproduction the length of reproduction and males It concerns mating whether it is assortative mating direct fitness or inclusive fitness It allows us to identify individuals Fishing industry healthy aquatic ecosystems Genetics can help by maintaining diverse stocks identifying invasive species or colonization and by identifying hybrid events and their directionality Conservation Genetics Conservation