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.
Well like many medical breakthroughs, there were a succession of findings by many scientists which led to an ultimate polio vaccine. But it was a scientist by the name of Dr Jonas Salk who, with the help of his colleagues at University of Pittsburgh Medical School, discovered the polio vaccine itself.Dr Jonas Salk was the son of Orthodox Polish-Jewish immigrants and was born in New York in 1914.owever there are other notable scientists who were either directly or indirectly involved with the discovery of the polio vaccine... Perhaps the most notable were Harvardâs Johns Enders and his team, who collectively discovered how to grow polio in test tubes a few years before the polio vaccine was discovered.