From Jim Harris
I was somewhat surprised to read that “some lines of laying hens share a staggering 90 per cent of their genes” (8 November, p 7), and that White Leghorns shared 15 per cent.
Since chimpanzees and humans share approximately 94 per cent of their genes, 90 per cent similarity suggests quite a diverse group.
Sharing just 15 per cent of genes would make White Leghorns different from just about every group of living organisms on the planet.
The editor writes:
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• We used the researchers’ phrasing: when they say two laying hens share one gene, they mean it is identical, with virtually the same sequence of base pairs coding for an identical protein. When other researchers say that cabbages and professors share one gene, they mean that it is, for example, a gene that when active produces the enzyme citrate synthase – though the sequences almost certainly differ in detail.
Ampthill, Bedfordshire, UK
