Cluster analysis as a methodology within phylogenetic systematics to construct phylogenetic trees

All evolutionary studies of groups of species are based on the choice of appropriate characteristics for rebuilding their phylogenies (a phylogeny is the relationship or kinship among species in general and tries to reconstruct evolutionary relationships). A phylogenetic analysis reconstructs the evolutionary relationships between species, which descend from common ancestors and, furthermore, which are the genetic distances or separation times between these species [1]. To generate a phylogenetic analysis characters must have two requirements: independent of each other and be homologous, they have the same origin and the same function in all organisms Study The nature of those characters can be varied. Any source of validated and proved phylogenetic information can provide characters for an evolutionary study. Among the main evolutionary studies that have been developed stand two methods: The methods that have been taken as morphological characters base in which the presence of physical characteristics that describe the species is identified, and methods that have been based on molecular characteristics as the sequence DNA [2]. These characters are recorded in a data matrix within which, the state in which the character has been observed is represented with zero if it is absent or one if present respectively, and whether it is a character that may be present in the species with different values (multi-state) within the data matrix can be represented by the value corresponding to that character [2]. For this reason, homologous characters, once they have been validated and proven, may be taken as the basis for an evolutionary study because they provide enough information for the reconstruction of a phylogenetic tree