Abstract
SUMMARYIn an attempt to correlate the rate of chromosome evolution with the rate of speciation, several authors have developed equations based on diploid numbers and the number of chromosome arms. In the present paper we have extended these formulae by including components for homologous elements (H), namely: chromosomal homologies (Hc); arm homologies (HeFN) and length measurements (LH) of the genomes involved in each comparison. Inversions, deletions and amplifications are considered separately as rearrangements (R). The present equation determines the index of karyological conservatism (KC) among any given pair of related species, taking values from 0 to 1. The new index of karyological distance (nKD) is then obtained from the expression nKD = 1—KC. Seven species from two genera of akodont rodents were analyzed by means of this equation and a phenogram illustrating their relationships constructed using the UPGMA program. The results show a closer association among species related at the suprageneric level than at the intrageneric level. This evidence stresses that phylogenetical distance is not necessarily correlated with karyological relationships.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
