Locating Pea Comb and Blue Egg in Relation to the Centromere of Chromosome 1 in the Chicken

A chromosome translocation involving the Z chromosome and Chromosome 1, the NM 7659 t(Z+;1q–), (T) was used in a genetic linkage test with pea comb (P) and blue egg (O). The translocation break point on Chromosome 1 is on the long arm, close to the centromere. It had been previously suggested that the loci for P and O are located on the short arm. Significant linkages of 10.4 ± 1.5 map units between P and T, 13.5 ± 2.4 map units between O and T, and 3.1 ± 1.1 map units between O and P were found. The linear order is T-P-O. The centromere of Chromosome 1 is between T and P, and P and O are located on the short arm. Muffs and beard was also segregating in this test and showed independence from all other markers.