Santa's Little Helper because there were animation problems with the others. Jean told the "Houston Chronicle" in 2001 that after the first episode was broadcast and "the next seven didn't have the dog, people wondered why." He also said in 2003 that the staff enjoyed the first episodes that centered on him, particularly "Simpsons Roasting on an Open Fire", which is the reason that more episodes about him were written. Writer John Swartzwelder has noted that the staff members of the show write the character Homer in the same way that they write Santa's Little Helper: "Both are loyal. Both have the same
Helper dependent virus and capsid encoding DNA, plus helper DNA. Every cell that is successfully transfected with all three DNA fragments will produce the necessary proteins to produce infective viruses. These viruses will only have transgenic DNA encapsidated and therefore once they've infected a patient's cell, they will not be capable of reproducing. Helper dependent viruses can also occur in nature without being "gutted". The term satellite virus has been given to a large group of viruses that all require the presence of another virus to replicate. Many of these are plant viruses, but animal viruses can be seen in the case of