Figure 2. Evolutionary layers of the X and Y chromosomes. (a) Comparative mapping of genes from the human X in marsupial mammals detected an ancient region conserved on the X in all mammals and denoted XCR, as well as a recently added region denoted XAR that is autosomal in marsupials.
Poliovirus, the causative agent of poliomyelitis (commonly known as polio), is a human enterovirus and member of the family of Picornaviridae. Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long.
What Having Had Polio Causes, Might Cause. and Does Not Cause. Marny K. Eulberg, MD, Family Practice, Denver, Colorado. continued, page 3. Attributing symptoms or changes in. functioning to oneâs previous polio. when the symptom is, in fact, due to. a disease or condition that should be. treated by an entirely different medi-. cal regime than polio/post-polio is not. only not helpful but may be danger-. ous.