Quantitative genetics stems off population genetics. It focuses mostly on phenotypes, the genes that make up our characteristic and traits on a visual level, and the ones that vary. It does not put as much emphasis on easily identifiable phenotypes like eye color or the presence of biochemical.

Like population genetics, quantitative genetics use the frequencies of alleles in genes. This is focused to gamodemes (breeding populations genes), and combines these with Mendelian inheritance. Because population genetics focuses on certain genes and their metabolic products, quantitative genetics studies the outer phenotypes, and notes the underlying genetics.

Because phenotypic values are continuously distributed, quantitative genetics uses stats to link phenotypes to genotypes. There are certain phenotypes that are analyzed as discrete categories or continuous phenotypes. This depends on the definition on of cut off points, or how they are quantified through metric.

Gene effects are one of the fundamentals of quantitative genetics. This is studying mother and father genes passed down to the children. Sir Ronald Fisher, who is the founder of quantitative genetics, studied how genes would interact at epistasis (a gene dependent on another gene existing).

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