DNA COMPONENTS OF THE CHICKEN GENOME

The organization of the chicken genome was investigated by centrifuging chicken DNA (Mr= 57 × 106) in preparative Cs2SO4/Ag+ and Cs2SO4/BAMD density gradients [BAMD = 3,6‐bis(acetato‐mercurimethyl)dioxane]. An analysis by CsCl density gradient of the DNA fractions obtained from the preparative experiments revealed that 88% of the genome is made up of four DNA components, characterized by buoyant densities of 1.699, 1.7025, 1.7045 and 1.708 g/cm3, and representing 39%, 25%, 15%, and 9%, respectively, of the total DNA. The remaining 12% of the genome is formed by seven minor and/or satellite components. The distribution of the ovalbumin gene in a Cs2CO4/BAMD density gradient, as tested with a cloned cDNA probe, coincides with the distribution of the 1.7025‐g/cm3 component. This shows that the DNA regions flanking the ovalbumin gene are homogeneous in base composition over long distances and that the gene is located on a DNA segment belonging to the 1.7025‐g/cm3 component. Copyright © 1979, Wiley Blackwell. All rights reserved