It turned out to be a very astute deal. The business, with its ready-made client base, started generating revenues straight away and grew rapidly as it took on more customers. But the founders never expected it to grow as fast as it did. Back then, it cost $10m (£6m) to sequence one person’s DNA, limiting the amount of research in the field. But in the intervening years, the cost of sequencing DNA has plummeted to less than $1,000, ushering in the era of “personalised medicine”, when every patient’s DNA can be decoded to discover which drugs will work best for them. This breakthrough is particularly tantalising in cancer research, where the same type of tumour can be caused by completely different genetic mutations, and has opened the floodgates for the application of Horizon’s technology.