The big one (final)

• Genetics is the branch of biology concern with a study of heredity and variation. It is the study of the origin, transmission and expression of genetic information.
• How did the field of genetics develop?

  Archaeological evidence suggests that humans have observed desirable traits in organisms in heredity of these traits for thousands of years
• Aristotle came up with spontaneous generation. Spontaneous generation states that all living organisms spontaneously arose from nonliving material.
• The invention of the microscope was in the 1600’s and led to the discovery of cells and microscopic organisms
• William Harvey (1600’s-1700’s) came of with the theory of epigenesis. that theory states that adult organisms develop over time from a fertilized egg
• Swammerdam and bonnet (1600-1700’s) came up with the theory of preformation. This theory states that the fertilized egg contains a complete miniature adult
• Schleiden and scwann (1830):

  • the cell theory- all organisms are composed of basic structural units called cells. All cells came from a previously existing cell.
• Louis Pasteur (1850’s):

  his swan neck flask experiments disproved spontaneous generation
• • 1859: Darwin published his ideas on the theory of evolution in The Origin of Species
• Descent with modification: Existing species arose from other ancestral species
• • Natural selection: The mechanism for evolutionary change
• • 1866: Mendel publishes his findings
• Mendel worked with peas and used quantitative data to support his ideas

  • Traits are passed from generation to generation
  • Transmission of genetic information from parents to offspring
• • His work forms the foundation for genetics:
  • Defined as the branch of biology concerned with the study of heredity and variation
• Sutton and Boveri (1900’s) independently developed the chromosomal theory of inheritance:

  • Inherited traits are controlled by genes residing on chromosomes transmitted through gametes, maintaining genetic continuity from generation to generation.
• There are four different types of bases found in DNA: adenine, thymine, cytosine and guanine
• DNA is composed of nucleotides which consist of three components: sugar, phosphate group and nitrogenous base
• Adenine always pairs up with Thymine
• Chromosomal theory of inheritance: Inherited traits are controlled by genes residing on chromosomes
• • Most eukaryotes have a characteristic number of chromosomes
  • Called diploid number (2n)
• Chromosomes in diploid cells exist in pairs called homologous chromosomes
• Genes are transmitted through gametes

  • Maintains genetic continuity from generation to generation
  • What is a gamete and how is it produced?
• Meiosis:

  • Chromosomes are copied and distributed
  • Resulting cells (gametes) receive only half the number of chromosomes
  • Are haploid (n)
• Mitosis

  • Chromosomes are copied and distributed
  • The two resulting daughter cells each receive a diploid set (2n)
• • Alleles
  • Variations of a gene
• genotype: the genetic makeup of an organism, expressed as a combination of alleles
• Phenotype

  • Expression of the genotype
  • Produces an observable trait or phenotype
• Gene expression

  • DNA → RNA → Protein
  • DNA is transcribed to RNA
  • RNA is translated into protein 
  • This is known as the central dogma of genetics
• • Proteins are the end product of gene expression
  • Protein action or location in a cell produces phenotype(s)
  • Diversity of proteins
• The Age of Genetics:

  • 1865: Mendel set the stage for the study of genetics
  • Genetics rapidly developed from Mendel’s peas to the Human Genome Project
  • 1962: Nobel Prize awarded to Watson, Crick, and Wilkins
  • Numerous Nobel Prizes have been awarded since then in the field of genetics
• Classical or forward genetics

  • Identifying the genes that caused mutant phenotypes
• • Reverse genetics
  • D N A sequence of a particular gene of interest (G O I) is known, but its function is not
• • Gene knockout
  • Allows scientists to render genes nonfunctional to investigate the possible role of that gene
• • 1970s: researchers discovered that restriction enzymes in bacteria cut viral DNA at specific sites
• Restriction enzymes allowed the advent of recombinant DNA and cloning

  • Recombinant DNA technology
  • The ability to transfer genes across species
• • Genomics
  • Studies the structure, function, and evolution of genes and genomes
• Proteomics

  • Identifies a set of proteins present in cells under a given set of conditions
  • Studies their functions and interactions
• Bioinformatics

  • Uses hardware and software for processing nucleotide and protein data
• CRISPR is an RNA molecule

  • Recognizes and binds to its corresponding DNA sequence
• • Cas is a nuclease
  • An enzyme that cleaves DNA at a specific site in a specific way.