white egg layer
Gallus gallus
Genomic DNA was extracted from 30 *l of blood from 25 unrelated F0 individuals from white egg layer lines using a Puregene DNA isolation kit (D-70KA; Gentra Systems, Inc., USA).  The RRLs were prepared by digesting 25 *g of pooled DNA using 1,000 units of the restriction enzyme AluI in a total volume of 240 *l. The selection of the restriction enzyme was based on the 10-fold reduction of genome complexity in the optimum size range (150-200 bp) of the sequencing technology platform (Genome Analyzer, Illumina). The digested DNA sample was fractionated on a 10% precast polyacrylamide gel (Biorad) at 100 V for 3 h and stained with ethidium bromide. The size fractions were sliced out of the gel and the DNA was mechanically sheared and  and eluted over night in 300 *l recovery buffer (8 mM Tris pH 8.0, 0.08 mM EDTA, 1.25 M ammonium acetate. After a 15-min incubation at 65*C, the eluent was purified using a Montage DNA Gel Extraction Device (Millipore Corporation, Bedford, MA) and precipitated with isopropanol. The DNA was washed with ethanol and re-suspended in DNA hydration solution (Gentra Systems, Inc., USA).