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 normal gene is dominant and thus considered natural and the abnormal gene is said to be recessive (lethal) in nature. Thus, the differed genes are termed as alleles. A genetic trait with recessive genes (genotype) is always harmful in physical expression (phenotype). For example, hemophilia (bleeding disease), albinism ( lack in melanin pigment) and retinoblastoma (eye disorder) are all due to recessive genetic conditions or disorders.