It is 41 bases (or nucleotides) long. In this example, the flanking sequences consist of 9 bases (although in reality flanking regions are typically much longer). The eight four-base repeat units (GATA) make up the remaining 32 bases. How long would you expect an allele from this same locus to be if it had 10 repeat units?
Try again. Make sure you add up the number of bases in the repeat units and the flanking sequences.
Correct. For this sequence, an allele with 10 repeat units would be 49 bp long.
Try again. Remember that larger fragments migrate slower than smaller fragments.
Correct. An allele that has 10 repeats would migrate slower than the current band with eight repeats.