KoT: an automatic implementation of the K/θ method for species delimitation

Abstract

AbstractK/θ is a method to delineate species that rests on the calculation of the ratio between the average distance K separating two putative species-level clades and the genetic diversity θ of these clades. Although this method is explicitly rooted in population genetic theory, it was never benchmarked due to the absence of a program allowing automated analyses. For the same reason, its application by hand was limited to small datasets of a few tens of sequences.We present an automatic implementation of the K/θ method, dubbed KoT (short for “K over Theta”), that takes as input a FASTA file, builds a neighbour-joining tree, and returns putative species boundaries based on a user-specified K/θ threshold. This automatic implementation avoids errors and makes it possible to apply the method to datasets comprising many sequences, as well as to test easily the impact of choosing different K/θ threshold ratios. KoT is implemented in Haxe, with a javascript webserver interface freely available at https://eeg-ebe.github.io/KoT/