Animal Cell Meiosis
To view this animation on Apple or Android phones and tablets, get Puffin Browser.
Download Meiosis study aid for this animation (free)
Download this animation and its matching PowerPoint® ($).
Meiosis is important in assuring genetic diversity in sexual reproduction. Use this interactive animation to follow Meiosis I (reduction division) and Meiosis II in a continuous sequence or stop at any stage and review critical events.
Events during Meiosis
Diploid Cell (2N): From a preceding mitotic division, the Oogonium (Spermatogonium) enters meiosis with DIPLOID (2N) chromosomes but TETRAPLOID (4N) DNA. Chromosomes then duplicate to produce SISTER CHROMATIDS (or HOMOLOGOUS DYADS).
Prophase I: Dyad pairs align to create "TETRADS", non-sister chromatids connect and trade sections at a "CHIASMA", a process called "CROSSING OVER".
Metaphase I: SPINDLE FIBERS attach to each dyad at the KINETOCHORE. Tension from spindle fibers aligns the tetrads at the cell equator.
Anaphase I: Chiasmata break apart and sister chromatids begin migrating toward opposite poles.
Telophase I: CLEAVAGE FURROW forms beginning the process of CYTOKINESIS (cell division). Resulting daughter cells are HAPLOID (1N).
Prophase II: Spindle formation begins and centrosomes begin moving toward poles.
Metaphase II: Tension from spindle fibers aligns chromosomes at the metaphase plate.
Anaphase II: CHROMATIDS separate and begin moving to the poles.
Telophase II: CLEAVAGE FURROW forms beginning CYTOKINESIS.
Gamete (1N): NUCLEAR ENVELOPES form and chromosomes disperse as CHROMATIN. Meiosis has produced 4 DAUGHTER CELLS, each with 1N chromosomes and 1N DNA. Later, in fertilization, male and female 1N gametes will fuse to form a 2N ZYGOTE.
sexual reproduction, reduction division, crossing over, kinetochore, microtubule