Word Origin and History for mesopotamian. ancient name for the land that lies between the Tigris and Euphrates rivers (in modern Iraq), from Greek mesopotamia (khora), literally a country between two rivers, from fem. of mesopotamos, from mesos middle (see medial (adj.)) + potamos river (see potamo-).
Monogenic forms, caused by a single mutation in a dominantly or recessively inherited gene, are well-established, albeit relatively rare types of PD. They collectively account for about 30% of the familial and 3%â5% of the sporadic cases.
Lesson Summary. In summary, traits that are polygenic are controlled by two or more genes. The Swedish geneticist Nilsson-Ehle used wheat and kernel color to first explore the concept of polygenic inheritance.olygenic Traits. If you were to graph out a trait or phenotype that is polygenic, you would notice a trend. These traits have what's called continuous variation, showing a bell curve of values for the phenotype.