Optimum pH for nuclear sex identification using quinacrine

Area of Science:

• Cytogenetics
• Molecular Biology
• Cell Biology

Background:

• Quinacrine dihydrochloride staining is a method for visualizing chromosomes.
• Accurate differentiation of X- and Y-chromatin is crucial for genetic analysis.
• The pH of mounting buffers can affect the fluorescence intensity and clarity of stained nuclei.

Purpose of the Study:

• To determine the optimal pH for quinacrine staining of interphase nuclei.
• To achieve precise differentiation between X- and Y-chromatin using buccal smears and hair root sheaths.

Main Methods:

• Interphase nuclei from buccal smears and hair root sheaths were stained with quinacrine.
• Preparations were mounted in MacIlvaine's buffer across a range of pH values (2-8).
• Nuclear fluorescence intensity and chromatin differentiation were evaluated at different pH levels.

Main Results:

• High pH (5-8) resulted in intense nuclear fluorescence.
• Lower pH (2-4) reduced background fluorescence, revealing distinct granules.
• Optimal differentiation of X-chromatin was observed at pH approximately 3.0.
• Optimal differentiation of Y-chromatin was observed at pH approximately 5.5.

Conclusions:

• The pH of the mounting buffer significantly impacts quinacrine staining efficacy.
• Specific pH values optimize the visualization of X- and Y-chromatin for genetic screening.
• This study provides guidelines for improved chromatin analysis using quinacrine fluorescence staining.