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.
  Polygenic traits are [characteristics of organisms that are] â¦  influenced by several genes.    So multiple alleles are more than two alleles for one trait, and  polygenic traits are one trait that is influenced by mulitple  genes. polygenic trait is a trait in which multiple sets of alleles are used to determine the trait, whereas in a single gene trait aka. a Mendelian trait, only one pair of alleles â¦ is used.