| Citation | Adrian Bird is the leading authority on DNA methylation in animal cells. He demonstrated a rolling circle mechanism for ribosomal gene amplification. He showed that DNA methylation sites can be mapped using restriction enzymes and thus showed semi-conservative copying of methylation patterns. He showed convincingly that the doublet CpG is a source of mutation in vertebrates which led to the use of 'GpG' restriction enzymes to detect polymorphisms linked to genetic diseases. He discovered unmethylated 'HTF' islands at the 5i ends of housekeeping genes. This discovery has allowed new strategies for mapping and identifying genes and it has allowed Bird to propose that the unmethylated HTF islands identify DNA sequences to be kept constantly available within the nucleus. |