A<unk>  is any graph used to visualize evolutionary relationships (either abstractly or explicitly) between nucleotide sequences, genes, chromosomes, genomes, or species. They are employed when reticulation events such as hybridization, horizontal gene transfer, recombination, or gene duplication and loss are believed to be involved. They differ from<unk>  trees by the explicit modeling of richly linked<unk> s, by means of the addition of hybrid nodes (nodes with two parents) instead of only tree nodes (a hierarchy of nodes, each with only one parent).<unk>  trees are a subset of<unk> s.<unk> s can be inferred and visualised with software such as SplitsTree, the R-package, phangorn, and, more recently, Dendroscope. A standard format for representing<unk> s is a variant of Newick format which is extended to support<unk> s as well as trees. Many kinds and subclasses of<unk> s have been defined based on the biological phenomenon they represent or which data they are built from (hybridization<unk> s, usually built from rooted trees, ancestral recombination graphs (ARGs) from binary sequences, median<unk> s from a set of splits, optimal realizations and reticulograms from a distance matrix), or restrictions to get computationally tractable problems (galled trees, and their generalizations level-k<unk> s, tree-child or tree-sibling<unk> s).
Phylogenetic network
Rape statistics
Test panel
Consensus error grid
Phenotypic disease network 
Functional molecular infection epidemiology
EFAR System Model
Kick chart