Skip to content

Phylogenetic Network with Reticulation Events

Run the Phylogenetic Network with Reticulation Events MicroSim Fullscreen

About This MicroSim

This MicroSim displays a phylogenetic network — an extension of a phylogenetic tree that can represent reticulation events such as hybridization, horizontal gene transfer (HGT), and recombination. Tree edges are shown in teal, while reticulation edges are shown in orange.

Tree vs. Network

  • Teal edges — Standard tree edges representing vertical inheritance (parent to offspring)
  • Orange edges — Reticulation edges representing non-tree-like events (hybridization, HGT, or recombination)
  • Toggle checkbox — Show or hide reticulation edges to compare the tree-like view with the full network

Why Phylogenetic Networks?

Traditional phylogenetic trees assume strictly bifurcating descent. But many biological processes violate this:

  • Horizontal gene transfer in bacteria transfers genes between unrelated lineages
  • Hybridization in plants and animals creates offspring from two distinct species
  • Recombination in viruses shuffles genetic material between strains

Phylogenetic networks capture these complex evolutionary histories that trees cannot represent.

How to Use

  1. Toggle reticulation events — Use the checkbox to show/hide orange reticulation edges
  2. Compare views — With reticulation hidden, you see a standard tree; with reticulation shown, you see the full network
  3. Hover over nodes and edges for details about each taxon and evolutionary event

Iframe Embed Code

1
2
3
4
<iframe src="https://dmccreary.github.io/bioinformatics/sims/phylogenetic-network/main.html"
        height="510"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Grade Level

College introductory bioinformatics

Duration

15-20 minutes

Prerequisites

  • Understanding of phylogenetic trees
  • Concept of horizontal gene transfer and hybridization
  • Familiarity with evolutionary processes

Activities

  1. Exploration (5 min): View the network with and without reticulation edges. How many reticulation events are present? Which taxa are involved?
  2. Tree vs. Network (5 min): With reticulation hidden, describe the tree topology. Now add reticulation back — how does it change your understanding of the evolutionary relationships?
  3. Discussion (5 min): In which organisms are phylogenetic networks most important (bacteria, plants, viruses)? Why are simple trees insufficient for these groups?
  4. Assessment (3 min): Answer the reflection questions below.

Assessment

  1. What is a reticulation event, and why can't a standard bifurcating tree represent it?
  2. Give two biological processes that create reticulate evolutionary patterns.
  3. Why is horizontal gene transfer particularly common in bacteria?
  4. How does a phylogenetic network change the interpretation of evolutionary relationships compared to a tree?

References

  1. Phylogenetic network — Wikipedia
  2. Horizontal gene transfer — Wikipedia
  3. Hybrid (biology) — Wikipedia
  4. Reticulate evolution — Wikipedia