Expression data in the developing human retina at 19-20 weeks' gestation

The retinas of simian primates include a specialized, cone-rich, macula which regards the central visual field and mediates high acuity and colour vision. A prominent feature of the macula is the fovea centralis - a 1 mm-wide, avascular depression in the inner retinal surface that corresponds with a local absence of rods and a peak spatial density of cones in the outer photoreceptor layer. The arrangement of macular photoreceptors, and their specialized ‘midget’ circuits, are the neural substrate for high resolution vision in primates. Macular-specific photoreceptor loss and abnormal blood vessel growth within the macula are the major causes of untreatable vision loss worldwide. However, the genes that regulate specialization of the macula, and the causes of its vulnerability to degeneration, remain obscure. Microarrays were used to compare gene expression between macula and non-macular regions during a critical phase of human retinal vascular development. Keywords: Comparison of developing anatomical regions A 5 mm circular retinal biopsy was taken from the posterior pole (‘macula’ sample) from four human foetuses at 19-20 weeks gestation and another from the corresponding region immediately nasal to the optic disc (‘nasal’ sample). The remaining retina comprised the third sample region (‘surround’ sample). RNA was extracted from the three retinal biopsies from each specimen and hybridised onto individual Affymetrix arrays (total 12 arrays). Gene expression in the ‘macula’ region was compared with the ‘nasal’ and ‘surround’ regions, which served as baselines.