<prompt> Multifactorial inheritance is most likely to play a role in?Cleft lipMarfans syndromErythroblastis fetalisDowns syndrome  <response>: A quantitative trait locus QTL is a section of DNA the locus that correlates with variation in a phenotype the quantitative trait. Usually the QTL is linked to, or contains, the genes that control that phenotype. QTLs are mapped by identifying which molecular markers such as SNPs or AFLPs correlate with an observed trait. This is often an early step in identifying and sequencing the actual genes that cause the trait variation. Quantitative traits are phenotypes characteristics that vary in degree and can be attributed to polygenic effects, i.e., the product of two or more genes, and their environment. 