Investigating diversity

• How is genetic diversity investigated

  • direct study of base sequences of DNA
  • direct study of base sequences of mRNA
  • study of the amino acid sequence of the proteins encoded by DNA and mRNA
• These sequences can be used to investigate...

  • How closely-related two species are
  • Diversity within a certain species
• The more distantly-related two species, the more time has elapsed since they had a common ancestor = more opportunities for mutations to occur.
• The more the sequence differs, the more distantly-related.
• Limitations of using amino acid sequences

  • Same amino acid sequence but different DNA base sequences (genetic code is degenerate). Protein comparisons are less useful for closely-related organisms.
  • Mutations are subtle otherwise the protein would be dysfunctional and die out with the cell.
  • Protein must be common to both organisms.
  • Only looks into a single gene.
• How to investigate diversity

  1. Take random samples of the population
  2. Collect your data
  3. Calculate a mean
  4. Calculate a standard deviation of the mean
• Standard deviation

  A measure of the spread of values around the mean (only works for continuous variation)
• The larger the standard deviation, the larger the diversity.
• Before advancements in gene technology, genetic diversity was compared by...

  The frequency of measurable or observable characteristics.