Final answer:
The genetic signature of recent positive selection on a locus is indicated by a higher rate of non-synonymous substitutions, leading to advantageous traits that enhance evolutionary fitness.
Step-by-step explanation:
The genetic signature of recent positive selection on a locus is indicated by a higher rate of non-synonymous substitutions compared to synonymous substitutions in protein-coding genes. This can be detected using the ratio of non-synonymous to synonymous substitutions (dN/dS), where a ratio greater than 1 suggests that positive selection is occurring. Such a scenario means that the non-synonymous changes are favored by natural selection because they lead to advantageous traits, increasing an individual's evolutionary fitness.