What is a tetrad?

A tetrad refers to a structure formed during the process of meiosis when homologous chromosomes pair up. Specifically, during prophase I of meiosis, each chromosome consists of two sister chromatids, and when homologous chromosomes align with each other, they form a group of four chromatids. This configuration is known as a tetrad because it consists of four individual chromatids: two from each of the homologous chromosomes.

The crossing over that occurs in tetrads leads to genetic recombination, which increases genetic diversity in gametes. This process is essential for sexual reproduction, adding variance to the offspring. Understanding the concept of a tetrad is crucial for comprehending how genetic material is shuffled during the formation of gametes, ultimately playing a significant role in evolution and the genetic variation within populations.