[citation needed] Brownlee cloned and expressed human clotting factor IX,[15][16] providing a recombinant source of this protein for Haemophilia B patients who had previously relied on the hazardous blood-derived product.
With Merlin Crossley he helped discover the two sets of genetic mutations that were preventing two key proteins from attaching to the DNA of people with a rare and unusual form of Haemophilia B – Haemophilia B Leyden – where sufferers experience episodes of excessive bleeding in childhood but have few bleeding problems after puberty.
This lack of protein attachment to the DNA was thereby turning off the gene that produces clotting factor IX, which prevents excessive bleeding.
[7] His certificate of election and candidature reads:Distinguished for his work on the sequences of nucleic acids and their biological implications.
He contributed to the development of methods using 32P-labelling and two-dimensional fractionation techniques, which greatly accelerated the early RNA sequencing.