Final answer:
The second step of meiotic recombination or crossing over involves the synapsis of homologous chromosomes where they line up and prepare for the exchange of genetic material. This is followed by the actual exchange of DNA segments to create recombinant chromosomes, which enhances genetic diversity.
Step-by-step explanation:
The second step of meiotic recombination, or crossing over, involves the synapsis of homologous chromosomes, during which they align closely together. After synapsis, the actual exchange of genetic segments, known as crossing over, can occur.
During prophase I of meiosis, homologous chromosomes pair up to form a tetrad, which consists of four chromatids. This close pairing during synapsis facilitates the breakage and rejoining of DNA between non-sister chromatids of homologous chromosomes. The process creates recombinant chromosomes, which have a combination of alleles from both the maternal and paternal chromosomes. This exchange of genetic material relies on precise breaks and reattachments, leading to genetic diversity in the resulting gametes. The reshuffled alleles on the recombinant chromosomes contribute to the variation found in offspring compared to their parents.