Main articles: Growth hormone 1 and Growth hormone 2. Genes for human growth hormone, known as growth hormone 1 (somatotropin) and growth hormone 2, are localized in the q22-24 region of chromosome 17 and are closely related to human chorionic somatomammotropin (also known as placental lactogen) genes.
The short-run marginal cost (MC) curve will at first decline and then will go up at some point, and will intersect the average total cost and average variable cost curves at their minimum points.
However, because the marginal cost curve is a plot of the slope of the total cost curve, then the shape of the total cost curve also reflects the law of diminishing marginal returns. The flattening slope of the total cost curve for small quantities of output is due to increasing marginal returns.