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.
So multiple alleles are more than two alleles for one trait, and polygenic traits are one trait that is influenced by mulitple genes. This information came from my biology textbook, Biology: Principles and Explorations by Holt, Rinehart, and Winston.ultiple alleles are genes that have more than two alleles. An  example of this would be blood types, with ABO as three separate  alleles.   Polygenic traits are traits â¦ whose phenotype rely on alleles from  different genes.