Phylogenetics

Introduction

• Phylogenetics is a branch of biology that explores the evolutionary relationships among different species or groups of organisms.
• It relies on genomic sequencing and comparisons to determine the evolutionary history and relatedness of organisms.

Using Genomic Sequencing

• Genomic sequencing involves studying the genetic material (DNA) of organisms. By comparing the DNA sequences, scientists can uncover:
  • Lineage: The exact sequence through which species can be traced back to ancestor populations.
  • Sequence Divergence: How and when different lineages diverged from a common ancestor.

Phylogenetic Tree

• A phylogenetic tree is a visual representation of the evolutionary relationships among various species or groups of organisms.
• It is like a family tree, showing which species share a more recent common ancestor.

Key Lineages

• Comparison of genomic sequences has led to the classification of living things into three key lineages:
  1. Bacteria
  2. Archaea
  3. Eukaryotes

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Phylogenetics

Applications of Phylogenetics

• Phylogenetics has significantly enhanced our understanding of life's evolution on Earth. It has been used, along with fossil evidence, to deduce important evolutionary events, such as:
  • The origin of cells
  • The existence of a last universal ancestor, the common ancestor of all life on Earth
  • The emergence of photosynthetic organisms
  • The development of eukaryotes (organisms with complex cells)
  • The evolution of multicellular life
  • The diversification of animals
  • The emergence of vertebrates
  • The colonisation of land by plants