Fig. 1

PCA plots for the seven lines. The first three PCs were used to calculate the genetic relationships between the seven lines. Y1, Y2, and Y3 represent three lines of yellow-feathered meat-type chickens, W1, W2, W3 and W4 represent four lines of white-feathered meat-type chickens. The four white-feathered meat-type chicken lines were closely related, and three yellow-feathered meat-type chicken lines 101, 401 and 501 were closely related