BIOCELL GEN Lecture 6.1 genetics

• Point mutations
• Genome


  The biological information needed to build and maintain a living organism, encoded in its DNA and divided into discrete units called genes

  
• Life is specified by genomes. Every organism, including humans, has a genome that contains all of the biological information needed to build and maintain a living example of that organism.
• The biological information contained in a genome is encoded in its deoxyribonucleic acid (DNA) and is divided into discrete units called genes. Genes code for proteins.

  
• Comparative Genomics enables us to understand how our own genome functions and how we evolved
• Earth BioGenome Project


  A 'moonshot' for biology that aims to sequence, catalogue, and characterise the genomes of all of Earth's eukaryotic biodiversity over a period of 10 years

  
• The search for answers to deep questions, motivated solely by curiosity and without concern for applications, often leads not only to the greatest scientific discoveries but also to the most revolutionary technological breakthroughs.
• DNA contains genes which code for RNA, which can result in the production of proteins, and those proteins 'do things' in cells.

  
• In tomatoes, red fruit (R) is dominant to yellow fruit (r) and tallness (T) is dominant to shortness (t). If a plant with an RrTt genotype is crossed with a plant that is rrtt:
• Testcross


  The genotype of an unknown parent can be revealed when bred with a homozygous recessive individual. Devised by Mendel.
• All F1 hybrids are wild-type. In F2s the classic 3:1 ratio was present…but ONLY in males! This was the first evidence of a specific gene on a specific chromosome, which boosted evidence for the chromosome theory of inheritance. Such genes on a sex chromosome are called sex-linked genes.
• Each DNA stand has a leading strand and lagging strand at opposite ends of the replication 'bubble'.
• Helicases


  Enzymes which untwist and separate DNA helix

  
• Single-strand binding proteins


  Bind to separated strands and hold them apart
• Promoter


  A sequence that RNA polymerase binds to before initiating (beginning) transcription
• The ratio of adenine to thymine is 1:1 in DNA
• In eukaryotic cells, genes specify (code for) proteins in the following steps

  • transcription, RNA processing, translation
  • transcription, translation, RNA processing
  • RNA processing, transcription, translation
  • translation, RNA processing, transcription
  • translation, transcription, termination

  
• Telomerase is generally only present in germ-cell lines. Thus somatic cell DNA strands tend to get shorter with each division. May this limit life span?