What is the method of DNA sexing in the laboratory?

The molecular sexing method is based on the result of the amplification of a molecular marker located in the sex chromosomes of birds using the technique of the Polymerase Chain Reaction.

Our laboratory technicians identify a birds sex by using the Polymerase Chain Reaction (PCR) to amplify the chromo-helicase DNA binding protein (Chromo-Helicase DNA binding region, CHD) and subsequently separating the amplified fragments in agarose gels. The CHD region is characterized by being in the sex chromosomes Z (present in males and females) and W (present only in females) of all bird species. This region differs in its size depending on the chromosome in which it is located, so that the males (ZZ, carrying two copies of the Z chromosome) will show a single band on the agarose gels, while the females (ZW, carriers of both copies) of the sex chromosomes Z and W) will be identified by showing two bands. If you want more information about this, you can find it in this blog post.