Essential Genetics 6th Edition by Daniel Hartl

Exercise 7

Prior to the demonstration that messenger RNA is translated in consecutive, nonoverlapping groups of three nucleotides (codons), the possibility of an overlapping code had to be considered. Such overlapping codes could be rejected because they impose constraints on which consecutive pairs of amino acids could be found in proteins. To understand why, suppose that the standard triplet codons were translated with an overlap of two. (In other words, the last two nucleotides of any codon are also the first two nucleotides of the next codon in line.) Which amino acids could follow:
(a) Lys?
(b) Met?
(c) Tyr?
(d) Trp?