Describe what happens to chromosomes during single and double crossovers. Would we expect to see these happen in gamete (sperm and egg) formation or in body cells?
Refer to the explanation.
During crossing over, homologous chromosomes undergo synapsis, in which parts of homologous pairs of chromosomes are exchanged. This occurs during prophase I of meoisis, so it occurs during gamete formation, and results in greater genetic diversity.
In the image below, the green pair of sister chromatids is from the mother, and the yellow pair is from the father. They make up a homologous pair, which means they have the same genes, though not necessarily the same alleles. During synapsis, the homologous pairs of chromosomes cross over and exchange parts of their chromosomes with each other. After crossing over, the homologous chromosomes are a combination of genetic material from each parent.