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.
In single-gene diseases, a mutation in just one of these genes is responsible for disease. Single-gene diseases run in families and can be dominant or recessive, and autosomal or sex-linked.Pedigree analyses of large families with many affected members are very useful for determining the inheritance pattern of single-gene diseases. Table 1 includes some examples of single-gene diseases.n single-gene diseases, a mutation in just one of these genes is responsible for disease. Single-gene diseases run in families and can be dominant or recessive, and autosomal or sex-linked.