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.
So, Polio vaccine ending the polio outbreak in the first world? It's a completer MYTH. Also, very little is ever said about the origin of some of the third world Polio outbreaks, that being, the live attenuated vaccine itself. There are times that Polio breaks out AFTER a vaccination program with Sabin live virus.o, Polio vaccine ending the polio outbreak in the first world? It's a completer MYTH. Also, very little is ever said about the origin of some of the third world Polio outbreaks, that being, the live attenuated vaccine itself. There are times that Polio breaks out AFTER a vaccination program with Sabin live virus.