Consider the following process taking place during Meiosis and fertilization: a) Crossing over and exchange of genetic material

Question

Consider the following process taking place during Meiosis and fertilization: a) Crossing over and exchange of genetic material

 

 

Describe this process and write an explanation of how this process contributes towards genetic variation.

Answer 1

Meiosis involves two divisions: Meiosis I and Meiosis II

In prophase I of Meiosis I, homologous chromosomes will pair next to each other and exchange portions of their chromatids. This is called crossing over. Crossing over is important in sexual reproduction because it produces new combinations of alleles because the alleles on each homologous chromosome are being exchanged between maternal and paternal copy. Recombinant chromosomes are chromosomes that went through crossing over and exchanged genetic material. They have some DNA from the mom and some from the dad. However, it is important to remember that crossing over does not always result in recombinant chromosomes because it is possible for chromosomes to exchange genetic material but have the same DNA if the alleles for each gene on the maternal and paternal chromosomes are the same. Ultimately, crossing increases genetic variation.