a. To determine whether the deletion of two base pair was sequencing error, the genomes should be re-sequenced or a complimentary Deoxyribonucleic acid (cDNA) copy of the gene.
The deletion of two base pairs is observed when browsing through the genome sequence, which results in disruption of the reading frame. If the deletion was correct, then the result would be serious as it alters the template, which amino acids are to be read. If it is an error in sequencing, there would not be any serious effects. So, by seeing the results, we can determine whether it is deletion that causes mutation of the gene or it just a sequence error.
b. We can conclude that the mutation occurred in common ancestor of both chimpanzee and human after the divergence from the ancestor of gorillas.
Two-base pair deletion in the genomic sequence of gorilla resulted in mutation that evolved in humans and chimpanzees.
Chimpanzees and humans had last common ancestor 5 - 6 million years ago. Since that time, genetic differences have accumulated by mutations that have occurred in each lineage. Genome sequencing has revealed that there are 35 million single-nucleotide differences between chimpanzees and humans corresponding about 1.06 percent degree of divergence.
In addition, about 5 million insertions and deletions ranging in length from just a single nucleotide to more than 15 Kb contribute a total of 90 Mb of divergent DNA sequence. Most of the deletions and insertions are in the non-coding regions.