a

. Ribosomes, complex structures that assemble proteins, have themselves about 55 different proteins. At least 20 more proteins are required to attach the 20 standard types of amino acids to transfer RNA. DNA-binding proteins and other proteins, specifically enzymes, also participate in the process.

b

. Richard E. Dickerson, “Chemical Evolution and the Origin of Life,” Scientific American, Vol. 239, September 1978, p. 73.

“The amino acids must link together to form proteins, and the other chemicals must join up to make nucleic acids, including the vital DNA. The seemingly insurmountable obstacle is the way the two reactions are inseparably linked—one can’t happen without the other. Proteins depend on DNA for their formation. But DNA cannot form without pre-existing protein.”  Hitching, p. 66.

c

. “The origin of the genetic code presents formidable unsolved problems. The coded information in the nucleotide sequence is meaningless without the translation machinery, but the specification for this machinery is itself coded in the DNA. Thus without the machinery the information is meaningless, but without the coded information the machinery cannot be produced! This presents a paradox of the ‘chicken and egg’ variety, and attempts to solve it have so far been sterile.” John C. Walton, (Lecturer in Chemistry, University of St. Andrews, Fife, Scotland), “Organization and the Origin of Life,” Origins, Vol. 4, No. 1, 1977, pp. 30–31.

“Genes and enzymes are linked together in a living cell—two interlocked systems, each supporting the other. It is difficult to see how either could manage alone. Yet if we are to avoid invoking either a Creator or a very large improbability, we must accept that one occurred before the other in the origin of life. But which one was it? We are left with the ancient riddle: Which came first, the chicken or the egg?” Shapiro, p. 135.

“Because DNA and proteins depend so intimately on each other for their survival, it’s hard to imagine one of them having evolved first. But it’s just as implausible for them to have emerged simultaneously out of a prebiotic soup.” Carl Zimmer, “How and Where Did Life on Earth Arise?” Science, Vol. 309, 1 July 2005, p. 89.

d

. Tomas Lindahl and Richard D. Wood, “Quality Control by DNA Repair,” Science, Vol. 286, 3 December 1999, pp. 1897-1905.