Phylogenetics and dating with Naught random chat
We describe how it can be used to estimate phylogenies and divergence times in the face of uncertainty in evolutionary rates and calibration times.
Our approach also provides a means for measuring the clocklikeness of datasets and comparing this measure between different genes and phylogenies.
Ancestral relationships among species are commonly represented as phylogenetic trees (also called cladograms or dendrograms).
A cladogram is a physical diagrammatic representation of a hypothesis of inferred relationship between species.
Similarly, the common ancestor of humans/Neanderthals and chimpanzees existed approximately 6.5 million years ago.
Thus, since humans and Neanderthals share a common ancestor not shared by chimpanzees, we have reason to believe that humans are more closely related to Neanderthals than to chimpanzees.
For example, the common ancestor of modern humans and Neanderthals would be traced back to approximately 500,000 years ago.The evolutionary relatedness between species is reflected by branching pattern of the tree and the relative distance between species on the tree.Any two species will have a common ancestor at the point where their respective branches are traced back to intersect.Similar retracing can be done farther and farther back on the branches of the tree of life to connect the common ancestry humans have with unicellular species some billions of years ago.Cladograms can be constructed with the aid of technologies that estimate molecular divergences in key sequences of DNA or protein amino acids.