Automated Identification of Polytene Chromosomes Banding Pattern using Image Processing Techniques

Abstract

An automated method has been developed to identify the dark bands and light-inter bands in the Polytene chromosomes microscopic images using the digital image processing algorithms. Polytene chromosomes are specific interphase large chromosomes which have alternation of dark bands and lighter inter bands morphology. Analysis of these banding patterns is very important in many structural and functional biological researches such as chromosomes mapping, identify small chromosome mutations, identify taxonomic species, and classify the sibling species. The algorithm of banding pattern identification and analysis follows a step-by-step strategy and the overall system is modularized into three stages: preprocessing, segmentation and feature extraction. The preprocessing stage contains the techniques to prepare the image for segmentation; the techniques deal directly with the raw, possibly noisy, pixel values with denoising and contrast adjustment. The segmentation stage finds and establishes outlines of specific dark/lighter-inter bands using rolling ball algorithm and automatic thresholding techniques. The feature extraction stage obtains semantics of the banding pattern and useful quantitative parameters from the segmented bands. In this work, some samples of straightened Polytene chromosome microscopic images were analyzed with satisfactory results.