The key similarities and differences between mitosis and meiosis are that both Mitosis and Meiosis are two cell divisions that occur in eukaryotic cells and both initiate from a diploid parent cell. But, mitosis produces two diploid daughter cells that are genetically identical to parent cell while meiosis produces four haploid daughter cells which are not genetically identical to the parent cell.
Further, during growth and development, mitosis produces many cells in multi-cellular organisms while during reproduction, meiosis produces sexual cells. More to these, there are many other similarities and differences between mitosis and meiosis, which are detailed here after a brief introduction to mitosis and meiosis.
CONTENTS
1. Overview and Key Difference
2. What is Mitosis
3. What is Meiosis
4. Similarities Between Mitosis and Meiosis
5. Side by Side Comparison – Mitosis vs Meiosis in Tabular Form
6. Summary
What is Mitosis?
Mitosis is a type of cell division that produces two daughter cells that are genetically similar to the parent cell. Mitotic phase occurs via four subphases namely prophase, metaphase, anaphase and telophase. Furthermore, cytokinesis completes it by producing two daughter cells that are genetically identical to the parent cell.
Figure 01: Mitosis
Prophase is the first phase of mitosis; during this phase, centrosomes migrate into two poles of the cell, nuclear membrane starts to disappear, microtubules starts to extend, chromosomes condense more and pair with each other and sister chromatids become visible. Metaphase is the second phase of mitosis in which chromosomes line up at the metaphase plate and microtubules connect with the centromeres of each chromosome separately. During anaphase, sister chromatids split evenly and separate to migrate towards the two poles. Microtubules assist the pulling of sister chromatids towards the two poles. Telophase is the last phase of nuclear division. Here, two new nuclei are formed, and the cell contents are divided between two sides of the cell. Finally, during cytokinesis, cell cytoplasm divides to form two new individual cells.
What is Meiosis?
Meiosis is a type of cell division which occurs during gamete formation. It produces four daughter cells from a parent cell. The diploid parent cell divides into four haploid cells via two major divisions called meiosis I and meiosis II. Moreover, each cell division has four subphases: prophase, metaphase, anaphase, and telophase. Hence, meiosis has eight subphases and results in four daughter cells that are not genetically identical to the parent cell.
Figure 02: Meiosis
Furthermore, meiosis allows the production of genetically variable gametes. This is because bivalent formation and genetic mixing occur at points known as chiasma during prophase. Bivalent or tetrad is an association of homologous chromosomes formed during the prophase I of meiosis. Chiasma is the contact point where two homologous chromosomes form a physical connection or a crossing over. Crossing over results in genetic material mixing between homologous chromosomes. Therefore, the resulting gametes will obtain new gene combinations, showing the genetic variability among offspring.
What are the Similarities and Differences Between Mitosis and Meiosis?
Similarities Between Mitosis and Meiosis
- Mitosis and meiosis are two major cell cycles that occur in multi-cellular organisms.
- Both cycles initiate from a diploid parent cell.
- Both cell cycles produce daughter cells.
- They are important and take place repeatedly.
- Both types consist of subphases which are almost similar.
- Cytokinesis occurs during both cycles.
- DNA duplication occurs in each cycle.
- In both cycles, nuclear membrane disappears.
- Both cycles involve the formation of spindle fibers.
Difference Between Mitosis and Meiosis
Mitosis is a type of cell division that produces two genetically identical daughter cells that are diploid. In contrast, meiosis is a type of cell division which produces four genetically dissimilar cells that are haploid. Each process produces cells that are different in chromosome number. Mitosis produces two cells while meiosis produces four cells. Moreover, the daughter cells produced in mitosis are genetically identical to parent cell whereas daughter cells produced in meiosis are not genetically similar to the parent cell. Moreover, mitosis occurs during growth and development whereas meiosis occurs during sex cell formation. Most importantly, somatic cells divide by mitosis, and germ cells divide by meiosis. Genetic recombination occurs during meiosis, but not during mitosis.
Summary – Mitosis vs Meiosis
Mitosis and meiosis are two cell divisions. Mitosis produces genetically identical daughter cells, in contrast to meiosis, which produces genetically varied daughter cells. In both cycles, DNA duplicates and segregates into two sides of the cell. Furthermore, cytokinesis is common to both cycles. Overall, the fundamental processes are similar in both divisions. However, at the end of each cycle, resultant cells are different in chromosome number. Somatic cells divide by mitosis and germ cells divide by meiosis. Thus, these are the similarities and differences between mitosis and meiosis.
Reference:
1. “Phases of Mitosis.” Khan Academy, Khan Academy, Available here.
2. “Meiosis.” Wikipedia, Wikimedia Foundation, 11 May 2018, Available here.
Image Courtesy:
1. “Meiosis diagram” By Marek Kultys – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Mitosis schematic diagram-en” By Schemazeichnung_Mitose.svg: *Diagrama_Mitosis.svg: Jpablo cadtranslation: Matt (talk)Diagrama_Mitosis.svg: juliana osorioderivative work: M3.dahl (talk) – Schemazeichnung_Mitose.svgDiagrama_Mitosis.svg (CC BY-SA 3.0) via Commons Wikimedia