One of the reasons for the success of the smallpox eradication campaign was that small pox only occurred in humans. Smallpox is an extremely contagious and deadly virus for which there is no known cure. it is caused by two variants, Variola major and Variola minor. it is a disease of the past that was eliminated by worldwide vaccination.
1. These four factors can effect ways evolution occur:
<span>1.) Mutation
2.) selection
3.) Gene Flow
4.) Genetic Drift
2. </span>In biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.
Selection, in biology, the preferential survival and reproduction or preferential elimination of individuals with certain genotypes by means of natural or artificial controlling factors.
In population genetics, gene flow is the transfer of alleles or genes from one population to another.
<span>Genetic drift is the change in the frequency of a gene variant in a population due to random sampling of organisms. </span>
