Genome Size


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•  Comparison of genome size of T2 phage, Escherichia coli, Drosophila melanogaster, Homo sapiens and 

   Paris japonica

Genome size can vary greatly between organisms and is not a valid indicator of genetic complexity

  • The largest known genome is possessed by the canopy plant Paris japonica – 150 billion base pairs
  • The smallest known genome is possessed by the bacterium Carsonella ruddi – 160,000 base pairs

As a general rule:

  • Viruses and bacteria tend to have very small genomes
  • Prokaryotes typically have smaller genomes than eukaryotes
  • Sizes of plant genomes can vary dramatically due to the capacity for plant species to self-fertilise and become polyploid

Comparison of Genome Size in Different Organisms

genome size table

Variation in Genome Sizes For Different Types of Organisms

genome size graph