in the x direction, the water wants to flow in that direction) For a given hydraulic. conductivity, the vertical flow rate depends on the sum of the gravitational potential energy. gradient per unit weight of water (dz/dz =1) and the vertical gradient in soil water pressure.
Origin and spread of the 1278insTATC mutation causing TayâSachs disease in Ashkenazi Jews: Genetic drift as a robust and parsimonious hypothesis. Human Genetics 114 (4): 366â376. pmid 14727180.
Summary. 1  Tay-Sachs disease is a genetic condition common in Ashkenazi Jews and French-Canadians. 2  The faulty (mutated) gene stops the cells of the nervous system from producing an enzyme vital to the health of the brain and spinal cord.