Abstract: Objective To explore the expression of xeroderma pigmentosum complementation group G （XPG） gene in healthy Han population of different ages and to analysis the relationship between the mRNA and protein expression levels of XPG and age, which may provide a new molecular-biological indicator for forensic age determination. Methods Total 150 samples of peripheral blood were collected from healthy Han population of different ages. Total RNA of peripheral blood mononuclear cell （PBMC） were extracted by TRIzol method, and the relative expression of XPG mRNA in PBMC was detected by quantitative real-time PCR, and the protein expression levels of XPG in plasma were detected by ELISA. Results The mRNA and protein expression levels of XPG in ≤18 years old group were significantly different from 19-45 years old group and ≥46 years old group （P<0.05）, while there was no significant difference between 19-45 years old group and ≥46 years old group （P>0.05）. No significant sex differences were observed in mRNA and protein expression levels of XPG （P>0.05）. Conclusion The relative expression level of XPG mRNA in PBMC declines with the increase of age in younger age, while the protein expression level in plasma increases with age, and XPG gene can be used as one of new markers for forensic age estimation.

Key words: forensic genetics, forensic anthropology, xeroderma pigmentosum group G, quantitative real-time PCR, enzyme linked immunosorbent assay, age estimation