Bioinformatics: Phylogenetic Trees

Bioinformatics: Phylogenetic Trees

Genetical, mophological, Biochemical evidences are now showing that all organisms on earth are genetically related, so every scientist is searching for what's called "The Tree Of Life" that represents the Phylogeny of organisms.

What is Phylogeny?

Phylogeny is the history of organismal lineages as they change through time. It implies that different species arise from previous forms via descent, and that all organisms, from the smallest microbe to the largest plants and vertebrates, are connected by the passage of genes along the branches of the phylogenetic tree that links all of Life.



Phylogenetic tree:

The Phylogenetic tree or Evolutionary tree is a tree showing the evolutionary relationship between various species that are thought to have a common Ancestor.

Each node in the tree represents the most recent common ancestor of the descendants, the edge lengths in some trees correspond to estimated time. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units (HTUs) as they cannot be directly observed.

In Bioinformatics, Softwares align sequences of species that are thought to have a common ancestor ( multiple sequence alignment) , and calculate the distance between organisms (by using the number of mutations...etc), in the end it displays a graphical view of the tree with nodes and their corresponding edge lengths.

Any comments you are welcome.