Class 1 History of Genetics Earliest evidence of genetic manipulation Selective breeding due to wanting certain characteristics both in plants and animals 500 BC Hippocratic school of medicine o Aristotle describes the inheritance of traits o Theory of Epigenesis an organism developed from a fertilized egg o Theory of Preformation an organism develops from a smaller version of itself into its final state Humunculus o Cell Theory an organism is composed of basic units cells Led to a renaissance in biology Ex Darwin Darwin Origin of species Breakthrough in Genetics Gregor Mendel Augustinian monk At this time chromosomes had not been discovered Spent 10 years monitoring the appearance of pea plants Breakthrough Advances in Microscopy Leads to the chromosomal theory of inheritance o Proposed Genes are located on chromosomes Chromosomes Normally in pars Diploid Stage 2n 2 Types of Cell Division Mitosis 2n n o Responsible for most cells in our body Meiosis 2n 2n o Responsible for gamete formation Working with Fruit Flies Cheap Easy to maintain Helps study the inheritance of traits Short life cycle o Eye color Wild Type Red Variant Type White Helps study phenotypes and genotypes Genotype is reflected in phenotype but not always Studying Chromosomes Breakthrough 1940 s genetic material is DNA not protein o Now what is the structure DNA A T 2 Hydrogen Bonds G C 3 hydrogen bonds Antiparallel nature important for transcription Knowing the structure and mode of inheritance Central Dogma DNA RNA Protein This brings together the Genotype to Phenotype A genotype mutation would lead to a phenotype mutation o Sickle Cell Anemia Mutant hemoglobin Recombinant DNA Technology Most important aspect Cloning Drives the modern field of Biotechnology Biotechnology Plants Animals o Herbicide resistance o Transgenics Prenatal Diagnosis 3 risk Huge advance in last 3 decades Begins with advent of the human genome project Many ethical issues with sequencing peoples genomes o It will allow for determining possible disease that might arise Proteomics identifying all the proteins in cells Bioinformatics using computers to understand the nature of DNA 2000 s 2010 s Personal medicine based on personal genomes Class 2 Mitosis Meiosis Mitosis behavior of chromosomes in the creation of somatic cells Meiosis the behavior of chromosomes in the creation of gametic cells Fundamental to all life Transmission of genetic material between parent and offspring Genome in Prokaryotes In the nucleoid Unbounded Circular Attached to membrane The DNA replicates every time the cell divides Genome in Eukaryotes Membrane bound organelles Contained within the nucleus Centrioles play an important role Centrioles Non membrane bound Part of the centrosome Form the Microtubule organizing center MTOC Involved in organizing spindle fibers Chromosome Structure Nomenclature Mitosis Description Somatic Cell Division Development Produces 2 daughter cells identical to parental cells Diploid 2n Homologous Chromosomes Sister Chromosomes Pairs of chromosomes of chromosomes in an organism varies from species to species Homologous Chromosomes Before DNA Replication During Interphase Sister Chromosomes After DNA Replication S Phase of Interphase Sister Chromosomes Sister Chromatids Carry the same genes in the same order Locus position of a gene Alleles different forms of a gene ex eye color One sister chromosome from father and one from mother Mitosis Process All divisions use mitosis throughout growth and development Occurs during the cell cycle G0 no division occurs o Faulty mechanism can lead to cancer Interphase G1 Synthesis G2 M S DNA Duplication G1 Growth Stage G2 Growth Stage M Mitotic Stages Stages of Mitosis Interphase 1 2 Prophase starts to condense 3 Prometaphase really condenses and chromosomes become clear 4 Metaphase chromosomes align at metaphase plate 5 Anaphase chromosomes split at the centromere and migrate to the poles of the cell 6 Telophase nuclear envelope begins to form 7 Cytokinesis separation of cells How are chromosomes held together Attached by kinetochore Uses cohesin protein Eventually enzymes dissociate cohesion in order to separate chromatids Shugoshin helps against the degradation of cohesin Meiosis 2n n if fertilization 2n insert diagram from PowerPoint Meiosis achieves Genetic Variation chromosomes Stages of Meiosis 1 Unique combinations of maternal and paternal chromosomes 2 Process of Crossing over Genetic Exchange between homologous 1 Prophase I Key difference with mitosis homologous chromosomes do not act independent from one another homologous chromosomes are not autonomous Synapsis homologous chromosomes pair Synapsed chromosomes are now bivalent Homologs condense revealing sister chromatids tetrad Crossing Over is unique to meiosis Sister chromatids begin to pull apart Site of genetic exchange adds to genetic variation Chiasma 2 Metaphase I 3 Anaphase I pulled toward poles 4 Telophase I Cytokinesis End Result 2 diploid cells Meiosis II 1 Prophase II Key Transition immediately from Meiosis I Meiosis II This means it skips the S phase meaning it doesn t replicate the DNA which is why the end cell with be n instead of 2n 2 Anaphase II 3 Telophase II End Result 4 haploid gametes Gametic Formation I Spermatogenesis Spermatogonium Primary Spermatocyte MEIOSIS I Secondary Spermatocyte MEIOSIS II Spermatids Spermatozoa II Oogenesis Oogononium Primary Oocyte MEIOSIS I Secondary Oocyte First Polar Body MEIOSIS II Ootid Second Polar Body Ovum Compared with spermatogenesis This process has an unequal division of cytoplasm Explanation it needs a high concentration of cytoplasm in order to feed the egg and help with cell processes Polar Bodies may or may not divide again Spermatogenesis is continuous Question When does segregation of alleles occur Class 3 Mendelian Genetics Gregor Mendel Key Contribution Father of Genetics Publication 1866 IT took 4 decades for people to realize the importance of what he had discovered Showed inheritance of traits by using peas At this time there was no knowledge on genes chromosomes etc He gave the basis for Transmission genetics Why garden peas Followed 7 visible traits Phenotypes 1 Seed Shape 2 Seed Color 3 Pod Shape 4 Pod Color 5 Flower Color 6 Flower position 7 Stem Height Each plant he used was true breeding Monohybrid Cross P1 Parental Generation F1 First Generation F2 Second Generation Self fertilization selfing Example 1 Plant Monohybrid Cross He first crossed a tall plant with a
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