Key features of DNA-based phylogenetic trees include their topology showing ancestral relationships and branch lengths indicating genetic differences. Trees can be rooted or unrooted, with rooting using an outgroup to indicate the most basal ancestor. The main steps in DNA tree construction are sequence alignment, converting alignment data into a tree, assessing tree accuracy through bootstrap analysis, and using molecular clocks to date branch points. While gene trees are often more accurate than morphology-based species trees, they are not always equivalent as gene trees reflect gene divergence through mutation while species trees indicate reproductive isolation through speciation events. Molecular phylogenetics has many applications including clarifying human/primate relationships, tracing the origins of AIDS, and studying human prehistory through genetic