The sickle form of the hemoglobin gene is created when an adenine nucleotide is changed to a thymine. ... That single amino acid replacement in the -globin protein alters the shape and the chemistry of the hemoglobin molecule, causing it to polymerize and distort the red blood cell into the sickle shape.
Deductive reasoning.
Deductive reasoning is a type of reasoning where a general fact is broken down into a more specific case to make an inference. This general fact can be a broad branch of knowledge then gets into its parts that may comprise this broad knowledge.