Answer to Question #118407 in Cell Biology for Danielle

Question

What is a source of genetic variation that involves the swapping of sections of chromosomes during meiosis?

Answer 1

Crossing-over is the source of genetic variation that involves swapping of sections of chromosomes during meiosis. Crossing over is the process by which genetic material is exchanged in a germ line. Pairs of chromosomes align such that there is exchange of genetic material between non-sister chromatids of homologous chromosomes undergoing meiosis. This often results in allelic combinations in the daughter cells. In most cases, cross overs occur during the Meiosis I. Prometaphase starts with each of the chromosomes dividing to form sister chromatids that are identical. Thus, crossing-over targets homologous chromosome pairs with sister chromatids belonging to either homolog swapping segments of themselves at different points along the entire length of the participating chromosome. This is the point of genetic recombination.