Given a sequencing reaction length of approximately 500 successive nucleotides, what is the absolute minimum number of sequencing reactions needed to determine the complete human genome, excluding overlap and redundancy?

6.4 million

Explanation:

The human genome contains 3.2 billion bases (nucleotides).

Each reaction can sequence a read length of 500 nucleotides. We are excluding overlaps, and redundant sequences (which in reality would always happen when performing sequencing). Therefore, the minimum number of sequencing reactions is the total number of nucleotides in the genome divided by the length of read 3.2 billion : 500 = 6.4 million