Map of Life: Measuring and Visualizing Species ’ Relatedness with Molecular Distance Maps

We propose a novel combination of methods that (i) portrays quantitative characteristics of a DNA se-quence as a black-and-white image, (ii) computes pair-wise distances between these images, and (iii) uses these distances to output a map wherein each sequence is a point in a common Euclidean space. In the resulting Molecular Distance Map each point sig-nifies a DNA sequence, and the geometric distance between any two points reflects the degree of re-latedness between the corresponding sequences and species. Molecular Distance Maps present compelling visual representations of relationships between species and could be used for taxonomic clarifications, for species identification, placement of species in existing taxo-nomic categories, as well as for studies of evolution-ary history. One of the advantages of this method is its general applicability since, as sequence align-ment is not required, the DNA sequences chosen for comparison can be completely different regions in dif-ferent genomes. In fact, this method can be used to compare any two DNA sequences. For example, in our dataset of 3,176 mitochondrial DNA sequences, it correctly finds the mtDNA sequences most closel