L-shaped distribution of the relative substitution rate (c/μ) observed for SARS-COV-2's genome, inconsistent with the selectionist theory, the neutral theory and the nearly neutral theory but a near-neutral balanced selection theory: Implication on "neutralist-selectionist" debate. - Chun Wu; Nicholas Paradis; Phillip M. Lakernick; Mariya Hryb (Comput. Biol. Medicine, 2023)