Question

a newborns dna is screened for hearing loss. the codon sequence used as the check for normal hearing is tat aga gga ggc aag tcg taa. however, the newborns codon sequence comes back as tat aga gga gac aag tcg taa. what can be concluded regarding the infants codon sequence? the codon sequence has a deletion mutation. the codon sequence has a frameshift mutation. the codon sequence has a substitution mutation. the codon sequence has a translocation mutation.

Explanation:

Compare the normal and infant's codon sequences. In the infant's sequence, the 'GGC' in the normal sequence is changed to 'GAC'. A substitution mutation occurs when one nucleotide base is replaced by another. Here, a single - base substitution has taken place. It's not a deletion (no bases removed), frameshift (no insertion or deletion causing a shift in reading - frame), or translocation (no segments moved to other locations).

Answer:

The codon sequence has a substitution mutation.