Reply #6: Here's the information from Zoogen's site: [View All]

"DNA sexing uses the process PCR (Polymerase Chain Reaction) to visualize pieces of DNA from the sex chromosomes of each bird. As in mammals, avian gender is determined chromosomally. However, unlike mammals in which the male is heterogametic (XY) and the female homogametic (XX), for birds the situation is reversed: females are heterogametic (WZ) and males homogametic (ZZ). The gene CHD (chromo - helicase - DNA binding protein) is found on both the W and Z chromosomes as a pair of duplicated gene loci, CHD-W and CHD-Z. Although the coding DNA of these two loci is conserved, the lengths of the non-coding DNA differ. Using a single pair of CHD primers, the PCR enzyme essentially duplicates these segments of DNA thousands of times until they can be photographed on a special instrument. Since the sizes of the two PCR products from the W and Z CHD loci are different, males and females are easily identified. Thus a female, which has both a W and a Z chromosome, will have two different size bands; while a male, having two Z chromosomes, will have only a single band."

http://www.zoogen.biz

So it's WZ and ZZ. My bad.