Meiosis and Mitosis in Fruitfly

Prophase I

Sister chromatids

Non sister chromatids

Prophase I is a crucial stage of meiosis because it sets the stage for the genetic diversity observed in gametes. The crossing over and recombination of genetic material between homologous chromosomes ensure that the offspring will have unique combinations of genes from their parents.

Spindle fibres

Metaphase I

Homologus chromosome

Metaphase I is a crucial stage in meiosis because it contributes to the genetic diversity of the resulting gametes. The random assortment of homologous chromosomes along the metaphase plate means that each gamete will receive a unique combination of maternal and paternal chromosomes, increasing genetic variation in the offspring.

Spindle fibres connected to the centromere

Anaphase 1

Sister chromatids attached to centromere

Separation of daughter chromosomes

Anaphase I is a critical step in meiosis as it ensures that each daughter cell receives a unique combination of chromosomes, leading to genetic variation in the offspring. It is followed by the final stages of meiosis, including Telophase I and Cytokinesis I, which eventually result in the formation of haploid cells.

Telophase 1

Nuclear membrane reforms

It's important to note that the two daughter cells produced during Telophase I are genetically unique, as they contain a random assortment of maternal and paternal chromosomes. This genetic variation is crucial for generating diversity in the resulting gametes and, subsequently, the offspring. After Telophase I, the two haploid daughter cells will enter the second round of meiotic division (Meiosis II), further reducing their chromosome number and eventually forming the mature gametes.

Prophase II

Spindle fibres reappear

Prophase II is an essential step in meiosis, as it prepares the cell for the subsequent stages, Metaphase II, Anaphase II, and Telophase II. These stages work together to complete the division of the haploid daughter cells into mature gametes, each with a unique combination of genetic material.

Nuclear membrane breaks down

Metaphase II

Chromosomea align along the middle of the cell

The alignment of chromosomes in Metaphase II sets the stage for the orderly separation of sister chromatids during Anaphase II. This separation ensures that each gamete receives a haploid set of chromosomes with a unique combination of genetic material, which is essential for genetic diversity and successful reproduction.

Spindle fibres attached to the centromere

Anaphase II

Seperation of daughter chromosomes (with two sister chromatids)

Anaphase II results in the formation of four unique haploid daughter cells, each containing a distinct combination of chromosomes. These cells are ready to develop into mature gametes (sperm or egg cells), contributing to genetic diversity in sexual reproduction.

Telophase II

Nuclear membrane reforms

Telophase II represents the final step in meiosis, resulting in the formation of four genetically distinct haploid daughter cells in fruit flies. These cells are crucial for sexual reproduction, as they will fuse with haploid gametes of the opposite sex during fertilization to restore the diploid chromosome number in the zygote.

Interphase

After interphase, the cell is ready to enter mitosis, a process of nuclear division. It's essential to understand that interphase is not part of mitosis but the phase that sets the stage for it, ensuring that the cell is adequately prepared for division.

Chromatin

Prophase

Duplicated chromosome

Centrioles

Prophase is a crucial stage in mitosis because it marks the beginning of the process of segregating the duplicated genetic material into two daughter cells. It is characterized by dramatic changes in the organization and structure of the cell's genetic material and the formation of the mitotic spindle.

Spindle fibres

Nuclear envelope

Metaphase

Centriole

Spindle fibres

Metaphase is a pivotal stage in mitosis because it is when the cell ensures that all chromosomes are properly aligned and attached to the mitotic spindle. This alignment ensures that the resulting daughter cells will have the correct number of chromosomes and that genetic information is equally divided between them.

Chromosome

Anaphase

Anaphase is a critical stage in mitosis because it is responsible for the physical separation of genetic material. The movement of chromosomes to opposite poles of the cell guarantees that the two daughter cells will inherit the same genetic information, creating genetic continuity between the parent and offspring cells.

Seperation of daughter chromosome

Telophase

Telophase plays a crucial role in ensuring that each daughter cell receives a complete and identical set of chromosomes. It also prepares the cell for cytokinesis, where the cytoplasm will be divided between the two daughter cells, resulting in the completion of the cell division process.

Nuclear envelope

Cytokinesis

Cytokinesis marks the final step in the cell division process, ensuring that each daughter cell receives its share of cellular components, including organelles and cytoplasm. This division results in the formation of two genetically identical daughter cells, each capable of carrying out the functions of a fully developed cell.

Nucleoulous reappears

Two daughter cells