This method results in a read length that is less than 800 bases on average, but may be extended to over 1000 bases. While fully automated implementations of this approach were the mainstay from the original sequencing of the human genome, their chief limitation was the small amount of DNA that could be processed per unit time, referred to as throughput, as well as high cost, resulting in it taking roughly 10 years and three billion dollars to sequence the first human genome