A Simple and Robust Method for Sexing Ancient Bovine Bones

Abstract

We set up a simple method for sexing ancient bovine bones, generally attributed to a specific sex by morphological methods. ZFX/ZFY genes were chosen among the sex-specific sequences available in Genbank. The method, validated on 22 individuals of 11 cattle breeds, was used to analyze 3 roman and 9 medieval cattle bones. In no cases we have found a false attribution of sex. On the 12 ancient remains we always had a consistent outcome. Only in the case of PCR failure we couldn't attribute the sample to the gender, but in no cases we had inconsistent results since in our method the sex is determined by the amplification of both sequences in X and Y (if present) chromosomes. A short PCR product of 132bp in both chromosomes was amplified and digested with specific enzymes to discriminate X and Y amplicons. Digestion gives fragments of different length according to the sex chromosome. This method amplifies simultaneously both sex chromosomes, therefore presents the advantage of using less aDNA for the analysis and reduces the possibility of wrong assignments. This approach combines the advantage of being accurate and successful while it only relies on widely available and cheap equipment. The system is strong enough to be used with aDNA (ancient DNA) and it could be easily extended to other mammals.