The passenger pigeon has 1.3 billion base pairs in its genome.

Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome.

The precision of this, one of George's famous unreadable slides, nevertheless points out that there's a level of precision here right down to the individual base pair.

International agencies should support epidemiological studies on populations living in areas with high background radiation such as India, China, Iran and Brazil, covering not just cancer but also genetic anomalies, and the results should be critically analysed.