Abstract: Objective: This thesis intends to investigate whether there are sequence differences between the inbred strains of mice A / J and C3H/HeJ (C3H) onanalyze a puberty relevant quantitative trait loci locus (Quantitative Trait Locus, QTL) (DXMit68-rs29053133) on whether there are sequence differences affecting the phenotype in order inbred strains of mice A / J and C3H/HeJ (C3H) to help on screening of the candidate genes. Methods: To build a Specific Sections Replacement strain replacement for the region specific section based on the between A / J and C3H/HeJ (C3H) strain mices , and study the puberty traits of their females puberty traits. This QTL chromosome sequence differences in between A / J and C3H/HeJ in this QTL did not cause significant difference in the related traits phenotype. Conclusion: The results of this study showed that the genes with sequence differences in this QTL section of the mice region between A/J and C3H/HeJ are not among the candidate genes that cause the puberty phenotypic differences.