Quantitative sexing (Q-sexing) technique for animal
sex-determination based on X chromosome-linked loci:
Empirical evidence from the Siberian tiger
Alasaad S., Fickel J., Soriguer R.C., Sushitsky Yu.P., Chelomina G.
В журналеAfrican Journal of Biotechnology
Год: 2013 Том: 12 Номер: 1 Страницы: 14-18
Here we report a mammal sexing procedure based on the detection of quantitative differences between
females and males in the X-linked loci (quantitative sexing, Q-sexing). This novel technique was
validated using samples from Siberian tigers (Panthera tigris altaica) whose sexes were known. The Q-
sexing technique relies on the fact that amplifications proceeding exclusively from the two X
chromosomes in a female mammal should reach the threshold cycle (CT) in a real-time quantitative real
time polymerase chain reaction (qPCR) assay sooner than amplifications from the single male X
chromosome. Nevertheless, given that the amplification efficiency may vary between samples, results
have to be calibrated to a marker that does not vary in copy number between the sexes (for example, an
autosomal-linked locus). For this purpose we used quantitative real time polymerase chain reaction (RT
qPCR) assays to quantify the amount of three specific Siberian tiger microsatellite markers (X-/Y- and
autosomal-linked loci) in individual samples in order to determine the sex of an animal. A difference of
one CT between the X and the autosome-linked loci was detected in males, but no such difference was
present in female samples. The Q-sexing technique unambiguously separates female from male
Siberian tigers. The future of RT qPCR is bright as technology is becoming ever more rapid, cost-
effective, easier to use and capable of processing higher throughputs. Thus, we expect that our novel
technique for animal sexing will have a wide applicability, although further studies are still needed to
adapt it to other animal species using specific primers.