Essentials of Genetics 9th Edition by Michael Palladino William Klug, Michael Cummings, Charlotte Spencer

Exercise 5

The use of nucleotide sequence data to measure genetic variability is complicated by the fact that the genes of higher eukaryotes are complex in organization and contain 5? and 3 → Flanking regions as well as introns. Researchers have compared the nucleotide sequence of two cloned alleles of the ?-globin gene from a single individual and found a variation of 1 percent. Those differences include 13 substitutions of one nucleotide for another and 3 short DNA segments that have been inserted in one allele or deleted in the other. None of the changes takes place in the gene's exons (coding regions). Why do you think this is so, and should it change our concept of genetic variation?