Figure 1

Schematic representation of the broiler population structure. Genotyped pure lines and crossbred individuals were sampled from pedigree pure lines (right) and two broiler-crossbreeding programs (bottom). Among the pedigree pure lines, line B is a male line and both lines C and D are female lines. All genotyped birds (indicated by “*”) were sampled from male flocks. The genotyped birds from male and female lines were elite sires randomly sampled from three overlapping generations. A random sample of the B0 elite sires’ progeny (B1) was also genotyped. The field crossbred chickens (fBCD) were end-product meat birds, whereas the pedigree crossbred chickens (pBCD) were produced for the genetic evaluation of B1 sires. The CD mothers of the field and pedigree crossbred chickens were different but from the same generation of CD parents. The line B fathers of field and pedigree crossbred chickens were diverged for two to three generations.