The antibiotic resistance gene allows for selection in bacteria. However, many plasmids also have selectable markers for use in other cell types. A short single-stranded DNA sequence used as an initiation point for PCR amplification or sequencing. Primers can be exploited for sequence verification of plasmids.
Fossils are formed in different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.
Another person was also working with the same theory with Darwin, and he is Alfred Russel Wallace. His paper is entitled "On the tendency of Varieties to Depart Indefinitely from the Original Type". This then prompted Darwin to finish his theory and submit his paper to the Linnean Society of London.
