tetrad

chromosome

Also known as: bivalent

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July 14, 2026

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A tetrad refers to a group of four cells or, more specifically in biology, a group of four synapsed chromatids that become visible during the prophase I stage of meiosis. During meiosis, chromosomes condense, and homologous chromosomes pair up in a process called synapsis. Each of these paired chromosomes consists of two sister chromatids. Therefore, a tetrad, also known as a bivalent, is formed by two homologous chromosomes, resulting in a total of four chromatids. This stage is crucial for genetic diversity as it is when crossing over, the exchange of genetic material between homologous chromosomes, occurs.1234

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meiosis
Each pair of chromosomes—called a tetrad, or a bivalent—consists of four chromatids. At this point, the homologous chromosomes exchange genetic material by the process of crossing over (see linkage group). In metaphase I, the homologous pairs align at the cell’s equatorial plane. During anaphase I, the homologous chromosomes separate and…
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Each pair of chromosomes—called a tetrad, or a bivalent—consists of four chromatids. At this point, the homologous chromosomes exchange genetic material by the process of crossing over (see linkage group). In metaphase I, the homologous pairs align at the cell’s equatorial plane. During anaphase I, the homologous chromosomes separate and…
Read More