Quantitative Analysis of Mitotic Stage Occurrence Frequency in Roots
Introduction
This paper presents a quantitative analysis of the occurrence of mitotic stages in living cells. To investigate this phenomenon, DNA was extracted from strawberries, and utilizing the knowledge on DNA, mitotic stages occurrence in Allium root tips, and Vicia faba roots were investigated. Deoxyribonucleic acid (DNA) is a double helix strand found in chromosomes which is self-replicating and carries genetic material. The information contained in DNA is used during mitosis by the parent cell to replicate into two identical cells. This type of cell division is called mitosis, and it occurs in living cells, causing cell development in multi-celled organisms and reproduction in single-celled bodies. A cell undergoing mitosis completes six stages; the first stage is interphase, followed by prophase, then metaphase, and anaphase as the fourth stage. Telophase occurs at the fifth stage, and cytokinesis completes the cell development cycle through mitosis. In the interphase stage, chromosomes appear as threadlike chromatids in the nuclear envelope, and it is the preparatory stage for mitosis. In the prophase stage, the chromosomes pair up and proceed to line up at opposite sides along the cell’s mitotic spindle, ready for the next step. In the anaphase and telophase stages, the sister chromatids separate and the cell pinches in the middle. The cell progresses to separate into two daughter cells in the cytokinesis stage. This investigation considers four active steps. Various researchers have conducted studies to estimate the complete mitotic duration (Matgane, 1968) and the effects of multiple compounds on allium roots growth (Turkoglu, 2007). This research aims to identify and characterize the various phases of mitosis in root tips using both sectioned and squash root tips methods. Also, it assists the author in developing the skills on microscope usage and drawing of accurate scientific cell drawings. Onions, Allium cepa, are common plants that are used extensively in scientific research to study cell division. Since the root tip undergoes constant and rapid cell division, there is an abundance of cells to carry out conclusive research on the distribution of the various mitotic stages. The author hypothesized that all the four active stages of mitosis would occur in equal frequency when studied under a microscope. The basis for this hypothesis is that the duration of a mitotic phase affects the rate of each step. This fact implies that the length of each stage will increase the likelihood of spotting the same number of cells undergoing each phase.
Discussion
Allium’s sectioned root tip showed an uneven distribution of the phase frequencies. The duration of each mitosis stage is different. The duration of prophase is longer than that of anaphase, which increases the chance of higher cell count in the late stage. The number of cells undergoing each phase varied widely from 83 to 49, which is in line with the findings of (Jevensen and Kavaljian, 1958). The number of cells undergoing the prophase stage was higher than those undergoing the telophase stage. The number of cells decreases from the preliminary stage and then increases from anaphase to telophase in line with findings by Stephens (1984). The duration of a cell undergoing anaphase stage is relatively short. Such length diminishes the chance that a researcher would capture the data leading to a fewer number of cells at anaphase stage, which is supported by the results of Porter (1960). These findings further collaborated with the visualization of the Vicia faba root on the microscope. The majority of the cells observed were in the prophase stage except for two cells that were undergoing the metaphase stage. Therefore, all cell division stages in mitosis do not occur with the same frequency.
Overall, this experiment aimed to identify and characterize the phases of cell division using readily available substances which facilitate inexpensive DNA extraction for experimental analysis. The duration of a mitotic phase has a direct bearing on the cells’ population available for observation. Cells quantity decreases from prophase to anaphase and then increases for telophase. This behavior implies that the duration of the prophase stage is higher than that of anaphase. There is an uneven distribution of mitotic phases that nullifies the hypothesis that all active stages of mitosis occur with the same frequency.