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.
If the alleles are the same (TT or tt), the genotype is homozygous. If the alleles are different (Tt) the genotype is heterozygous. It is actually rare that 1 gene determines 1 characteristic as in the case of PTC tasting (a monogenic trait).Most traits are complex and have genes that affect them at more than 1 locus (polygenic).f the alleles are different (Tt) the genotype is heterozygous. It is actually rare that 1 gene determines 1 characteristic as in the case of PTC tasting (a monogenic trait). Most traits are complex and have genes that affect them at more than 1 locus (polygenic).