Thursday, January 20, 2011


Meiosis is what is known as a type of cell division in which the germ cells (eggs and sperm) are produced. Meiosis involves a reduction in the number of genetic materials. Two successive nuclear divisions with only one round of DNA replication is comprised in meiosis.

Interphase: Before meiosis begins, genetic material is duplicated.

First division of meiosis

Prophase 1: Duplicated chromatin condenses. Each chromosome consists of two, closely associated sister chromatids. Crossing-over can occur during the latter part of this stage.

Metaphase 1: Homologous chromosomes align at the equatorial plate.

Anaphase 1: Homologous pairs separate with sister chromatids remaining together.

Telophase 1: Two daughter cells are formed with each daughter containing only one chromosome of the homologous pair.

Second division of meiosis: Gamete formation

Prophase 2: DNA does not replicate.

Metaphase 2: Chromosomes align at the equatorial plate.

Anaphase 2: Centromeres divide and sister chromatids migrate separately to each pole.

Telophase 2: Cell division is complete. Four haploid daughter cells are obtained.

Four daughter cells are produced by one parent cell. Daughter cells have halod of the number of chromosomes found in the original parent cell , and due to crossing over are genetically different.

info from: and class discussions

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