Zinc-finger intron 7: a new locus for sex identification of giant panda (Ailuropoda melanoleuca).

We developed a single-reaction test for identifying the sex of giant panda (Ailuropoda melanoleuca) targeted to co-amplify homologous fragments with size polymorphism that located at zinc-finger (ZF) intron 7 by using one pair of primers. This assay produced one sex-specific fragment in females (XX genotypes) whereas two fragments were produced in males (XY genotypes). Indels (insertion/deletion) in intron 7 of Y-linked allele provide a significant discrimination between ZFX and ZFY, thus the amplification products can be simply distinguished by agarose gel electrophoresis, exhibiting sex-specific banding patterns (female, 354 bp; male, 354 bp, 135 bp). The new primer set was successfully tested on known-sex giant pandas by using template DNA extracted from both blood and fecal samples. Cross-species test was also performed, revealing that this assay could be applied to other Ursidae species.