Although native to Africa, Ostriches are now farmed all over the world for their meat, feathers and hide. Ostriches, like many bird species, show few external differences between the sexes. In the 1960's a surgical technique was developed to tell male and female birds apart, which involved a small operation under anaesthetic. However, this procedure can result in bleeding and infection, as well as being stressful for the birds. In addition, ostrich chicks must be around three months old before their sex can be distinguished in this way.
For most birds genetic tests have largely replaced surgery as a means of determining the sex of a chick. However, genetic tests are usually based on differences between genes carried on sex chromosomes. Unfortunately, the sex chromosomes in ostriches are very similar making these sort of genetic tests useless. Whilst some new tests have been devised, they are not suitable for the large-scale analyses that are needed by commercial ostrich breeders.
To solve this problem, researchers from Brazil have devised a fast, large-scale technique, which can be used to sex-type ostriches from feathers. They used feathers rather than blood samples because it is more practical for farmers and less stressful for the birds to collect feather samples. The procedure involves a genetic technique known as the polymerase chain reaction (PCR) which can "amplify" fragments of DNA that are specific to male or female ostriches. The researchers used their technique to sex-type 96 five-day-old ostrich chicks. Three months later, the sex of the chicks was also determined by using the traditional surgical technique. To their delight the researchers found that there was 100% agreement between the new genetic technique and the traditional surgical procedure, confirming that their method worked.
"We have established a fast, safe and inexpensive procedure for large-scale sex-typing of ostriches using DNA extracted from feathers. This procedure will be useful the gender identification of chicks in the first days of nestling life", explained the authors.
This article in freely available in the open access, peer reviewed journal, BMC Biotechnology http://www.
BioMed Central (http://www.