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.
The term âpolygenic inheritanceâ is used to refer to the inheritance of quantitative traits, traits which are influenced by multiple genes, not just one.In addition to involving multiple genes, polygenic inheritance also looks at the role of environment in someone's development.or example, sickle cell anemia is a form of pleiotropy, caused by a distinctive mutation in one gene which leads to a host of symptoms. In addition to causing mutations, pleiotropy also occurs in perfectly normal genes, although researchers tend to use it to track and understand mutations in particular.