DNA based sexing in finches helps me to avoid mistakes in male/female determination, so I can make correct pairs for breeding and save time refusing inappropriate breeding combinations. This method is equally effective for any bird species, as it is founded on detection of DNA sequences specific for sex chromosomes. Whereas in birds all males have two alike Z sex chromosomes in their genome, females carry one Z and one different W sex-chromosome. Therefore DNA sequences on the W chromosome can be used as genetic markers to identify sex in avian species. To detect these markers, it is necessary to amplify the specific marker sequence to detectable level. Polymerase chain reaction (PCR) provides generating millions of copies of targeted DNA strand. PCR products have to be separated then by gel electrophoresis to visualize different in size fragments of amplified marker DNA as bands. Typically, the gel electrophoresis reveals one band in the male and two in the female.

Here is a result of PCR amplification sex-linked markers from six birds. As you can see, I took into analysis here two females (F) – both of them have two bands, and four males (M), each of them has one band on the gel.