On this C57BL/6J congenic background this spontaneous mutation in Gnat2 causes homozygotes to have an abnormal light-adapted electroretinogram as early as 3 weeks of age, the earliest timepoint assessed. Fundus photographs are normal and no abnormalities are detected in retinal structure by 6 months of age in optical coherence tomography and histology. On the ALS/LtJ background, electroretinography shows that cpfl3 homozyogtes have poor cone-mediated responses evident by 3 week of age and completely lack cone-mediated responses from 9 weeks of age on. Rod-mediated responses are nearly normal, but with some diminution with age. Histology shows the normal 8 to 10 rows of rod nuclei at 6 and 15 weeks of age, but vacuolization and shortening of the photoreceptor outer segments is found at 27 weeks of age. Loss of immunohistochemical staining of cone-specific alpha transducin occurs by 4 weeks of age yet peanut agglutinin staining shows a normal number of cone outer segments at 14 weeks of age. Fundus photographs are essentially normal except for slightly dilated retinal veins and slightly contracted arterioles at 8 months of age.

This strain is temporarily available to pre-order live mice. Before placing an order, please read the Important Note below. Gnat2cpfl3 homozyogtes have poor cone-mediated responses evident by 3 weeks of age and completely lack cone-mediated responses from 9 weeks of age on. This strain provides a model for achromatopsia 4.