The first recombinant DNA was constructed by using a piece of DNA from a plasmid carrying antibiotic resistance gene in the bacterium Salmonella typhimurium and linked it to the plasmid of E. coll. , ,

Cohen and Boyer are known as father of genetic engineering. , , ,

When cut by the same restriction enzyme, the resultant DNA fragments have the same kind of sticky ends and these can be joined together using DNA \-times. , (E), (G), (H), (I)

Endonucleases remove nucleotides from the ends of the DNA whereas exonucleases make cuts at specific positions within the DNA. (E) Presence of more than one recognition sites within the vector will generate several fragments, which will complicate the gene cloning- (F) Humulin was the first recombinant DNA, based product, produced and marketed in India. (G) YAC vectors contain the telomeric sequence, the centromere and autonomously replicating sequence from yeast chromosomes. (H) Alkaline phosphatase, is used to- prevent unwanted self ligation of the vector DNA molecules in procedures of r DNA technology. (I) pBR322 vector was the first artificial ideal vector constructed by Boliver and Rodriguer. (J) Plasmid DNA is coated with histone proteins and can act as genetic factor. , (F), (J) , (E), (J) , (F), (J)