The theoretical model builds on the concept of continental drift developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s and early 1960s. The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken up into tectonic plates.
These disorders are known as monogenetic disorders (disorders of a single gene). Some examples of monogenetic disorders include: 1  cystic fibrosis, 2  sickle cell anemia,3  Marfan syndrome, 4  Huntington's disease, and.5  hemochromatosis.ome examples of monogenetic disorders include: 1  cystic fibrosis, 2  sickle cell anemia, 3  Marfan syndrome, 4  Huntington's disease, and. 5  hemochromatosis.
Single gene disorder is disease or disorder that is due to the effect on mutated gene. These disorders are quite rare and examples are Huntington's disease and sickle cell disease.SINGLE-GENE DISORDER: In a single gene disorder the mutation causes a failure to synthesise a functioning enzyme..ingle gene disorder is disease or disorder that is due to the effect on mutated gene. These disorders are quite rare and examples are Huntington's disease and sickle cell disease.