Punnett Square is a checker-board used to show the result of a cross between two organisms. The checkerboard was devised by a British geneticist, Reginald Punnett (1927). It depicts both genotypes and phenotypes of the progeny.

Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. The term "linkage" was coined by T.H. Morgan. Franklin Stahl with Matthew Meselson proved the semi-conservative replication of DNA. Spliceosomes are formed during post-transcriptional changes in eukaryotes. It is a complex, formed between 5' end (GU) and 3' end (AG) of the intron to remove it.
Transduction is a method of sexual reproduction in bacteria. It involves the transfer of foreign genes by means of viruses. It was discovered by Zinder and his researcher Lederberg (1952) in Salmonella typhimurium.