ADSC 2010 Lecture 19Outline of Last Lecture I. Other Unique FeaturesA. BabiesB. Rumen InoculationC. Symbiosis1. Microbes2. RuminantsII. Rumination and EructationA. RuminationB. EructationIII. VFA Usage = Energy RequirementsA. Absorbed…B. Travel Through…IV. Other NutrientsA. Dietary ProteinB. NPNC. VitaminsV. GeneticsA. General Cellular Structurea. Within the Nucleus1. Chromosomes2. Genes3. DNA4. NucleotidesB. Transcription and Translationa. Transcriptionb. TranslationVI. More about ChromosomesA. Chromosome Numbers1. Sex ChromosomesOutline of Current Lecture I. MitosisII. MeiosisIII. GametogenesisA. SpermatogenesisB. OogenesisIV. Genetic Life CycleV. Gene locusVI. Father of GeneticsA. Gregor Mendel B. Two types of inherited traitsVII. InheritanceVIII. Multiple Allele’s Current Lecture: I. Mitosis: process of cell division where two identical daughter cells are formed with the same compliment of chromosome pairs (diploid)- Process: diploid diploid1. Prophase2. Metaphase3. Anaphase4. TelophaseII. Meiosis: process of cell division where daughter cells (sperm/ova) contained ½ the number of chromosomes- Process: diploid haploid1. Prophase I2. Metaphase I3. Anaphase I4. Telophase I & Prophase II5. Anaphase II6. Telophase IIIII. Gametogenesis: production of gametesA. SpermatogenesisDiploid Primordial germ cell(spermatogonia)1Tetraploid Primary spermatocyteDiploid Secondary spermatocyteHaploid Spermatid 4Mature spermB. OogenesisDiploid Primordial germ cell(Oogonia)1Tetra Primary OoctyeDiploid Secondary OocyteHaploid Ootid 1Ovum CycleIV. Genetic Life CycleV. Gene locus: specific location of gene on a chromosome- Homologous chromosome: same location- Forms coding system that directs production of enzymes and proteins; controls the development of traits - Allele: different form of a gene that can occur at the same locus (ex. Coat color of cattle) B= Black, b = red (not black)- Homozygous: alleles at homologous gene sites are identical- Heterozygous: alleles are not identical- Genotypes: genetic make-up of individual determined by genes- Phenotype: physical expression of individuals - Genotype + environment = phenotype- Variation: measurable differencesGenetic Life Cycle• Sperm (n)Fertilization Zygote (2n) Mature Organism• Ovum (n){GametogenesisMitosisVI. Father of GeneticsA. Gregor Mendel- Austrian monk- 1st to understand inheritance a. Principle of segregation: paired genes (alleles) are separated from each other and distributed in different sex cellsb. Principle of independent assortment: alleles are separated independently into sex cells. Alleles have equal change of being included in a gamete.B. Two types of inherited traits1. Qualitative: controlled by 1-2 genesEx: coat color, horns, cryptorchidism, and inverted nipple2. Quantitative: affected by many genes and contain continuous variationEx: rate of gain, feed efficiency, milk production, carcass quality, fertilityVII. Inheritance: each allele has different effect on phenotypeA. Dominant: expressed allele, limits other allelesB. Recessive: expression limitedEx: coat color in AngusTwo alleles: B, b- Homozygous dominant (BB): black- Heterozygous (Bb): Black- Homozygous recessive (bb): Red- Six types of mating in Angus: (B= black, b= red)Bull CowBB BBBB BbBB bbBb BbBb bbbb bbEx: HornsP= dominant (polled): we prefer polled!!!p= recessive (horned: no real advantages…VIII. Multiple Allele’s - Scurred: horn tissue attached to skin of polled cattle, not
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