Evolutionary genomics: reading the bands.
The human genome is not a uniform structure but, instead, is a mosaic of bands. Some of these bands can be seen by the eye. Stained with Giemsa and viewed under the microscope each human chromosome has a prototypical pattern of light and dark bands (G and R bands respectively). Other bands are not so easily viewed. The human genome is, for example, a mosaic of isochores, blocks of DNA within which the proportion of the bases G and C at silent sites (introns, third positions in codons, intergene spacer) is fairly uniform. Recent work by Matassi and colleagues(1) has revealed what might be a new and unexpected banding pattern. They have found that the genes which are close together on the chromosome have similar rates of evolution. BioEssays 22:105-107, 2000.
Hurst
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LD
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
Eyre-Walker
A
A
D002871:Chromosome Banding; D002877:Chromosomes, Human / Q000235:genetics; D019143:Evolution, Molecular; D008040:Genetic Linkage; D015894:Genome, Human; D006801:Humans; D013997:Time Factors