Genetics and Evolution

• What is Genetics?


  Genetics is a branch of Biology that deals with heredity and variation of organisms.
• What are the tree branches of genetics?

  Transmission genetics, Molecular Genetics and Population Genetics
• What is Transmissions genetics?

  Examines how traits are passed down from one organism to the next generation.
• What is Molecular genetics?

  It deals with how the molecular features of DNA underlie gene expression. It is a detailed analysis of DNA, RNA and Proteins.
• What is Population genetics?

  Genetic variation of populations and how that variation is related to the environment. Population genetics feels with genetic variation and its role in evolution.
• Where is genetic material found?

  In DNA
• What do most human cells consist of?

  46 human chromosomes, 2 meters of DNA, Approximately 20,000 to 25,000 genes that code for proteins, and Approximately 3 billion DNA base pairs per set of chromosomes (A,T,G,C).
• Inherited differences in traits are due to

  Genetic variation
• What two things govern traits?

  Genes that encode the traits and the environment an organism lives in. (Nature vs. Nurture)
• What is Biological Evolution?

  It is the term used to explain the genetic makeup of a population that is changed over many generations.
• Genetics


  A branch of biology that deals with the heredity and variation of organisms
• Fields of genetics


  • Transmission Genetics
  • Molecular Genetics
  • Population Genetics
• Transmission Genetics


  Examines how traits are passed from one generation to the next
• Molecular Genetics


  Deals with how the molecular features of DNA underlie gene expression, including detailed analysis of DNA, RNA and proteins

  
• Population Genetics


  Deals with genetic variation of populations and how that variation is related to the environment
• Traits are not just governed by genes that encode them, but are influenced by the environment that the organism lives in
• Biological evolution


  The genetic makeup of a population can change over many generations
• Natural selection


  • Environment acts on genetic variation
  • Variants with greater reproductive success are more likely to pass their genes to future generations
• Genetic variation is random
• A variation that is beneficial in one environment may be detrimental in another
• Variation can also be neutral
• Evolution of Equus caballus (the modern day horse)

  1. Larger size

  2. Fewer toes

  3. Modified jaw for grazing
• There are evolutionary "Dead Ends"
• More than one hominoid existed at the same time
• Transmission Genetics


  Studies heredity, how traits transmitted or inherited from parent to offspring
• Early ideas of heredity

  • Pangenesis
  • Preformitism
  • Spermists
  • Ovists
  • Blending
• Gregor Mendel


  Father of Genetics
• Mendel's contributions in the 1860s
• Pea (Pisum sativum)


  • Short life cycle, grow in one season
  • Traits visible to the naked eye
  • Self-fertilizing, but can be cross-bred experimentally
  • True-breeding strains
• Mendel's experimental design


  1. Cross-pollination

  2. Self-fertilization
• Mendel's seven "either or" traits

  • Seed shape
  • Flower color
  • Flower position
  • Stem length
  • Pod shape
  • Pod color
  • Seed color
• Single-factor or monohybrid cross


  Involves a single pair of contrasting traits
• Reciprocal cross


  Mendel's single factor crosses were not sex dependent
• Mendel's first three postulates

  • Particulate unit factors (genes) exist in pairs
  • For a single characteristic, one unit factor is dominant and the other is recessive
  • The paired unit factors separate (segregate) independently during gamete formation
• Genotype


  The genetic makeup of an individual
• Phenotype


  The physical expression of the genetic makeup
• Homozygous


  Both alleles for a trait in an individual are the same
• Heterozygous


  Both alleles for a trait in an individual are different
• Dominant allele

  Usually capital letters
• Genetics


  A branch of biology that deals with the heredity and variation of organisms