During meiosis, crossing over occurs during prophase I. It is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes, which contribute to genetic diversity. More »

Crossing over begins very early in the prophase I stage of meiosis. During prophase I, pairs of homologous chromosomes exchange lengths of their genetic material. Crossing over leads to recombinant chromosomes and is a k... More »

Chromosomes form tetrads during the prophase I phase of meiosis, according to Biology Online. Tetrads occur when synapsis within the cell causes four chromatids to form as part of a homologous pair of chromosomes. More »

In a eukaryotic cell, chromosome replication occurs during DNA synthesis, or the S phase of the cell cycle. In its normal state, a chromosome is a long, thin chromatin fiber containing one DNA molecule. Once duplicated, ... More »

Homologous chromosomes do not pair during mitosis, so there is no opportunity for crossing over to occur. Crossing over between non-sister chromatids of homologous chromosomes occurs in meiosis during prophase I. More »

Meiosis II is a process that occurs in human sex cells. In order to duplicate, human sex cells undergo meiosis I followed by meiosis II. The coupled processes produce genetically different haploid daughter cells that eac... More »

Meiosis involves two rounds of nuclear division with the daughter cells receiving half the genetic material of the parent, while mitosis involves one. This ensures greater genetic variation. More »

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