Final answer:
Genetic recombination in meiosis is completed by the end of the pachytene stage, where homologous chromosomes undergo crossover events to increase genetic diversity in the resulting gametes.
Step-by-step explanation:
In meiosis, genetic recombination is completed by the end of pachytene. During the pachytene stage of prophase I, homologous chromosomes align closely along their entire length. This process, known as synapsis, forms a protein structure called the synaptonemal complex. Homologous recombination, also termed crossover, then takes place between nonsister chromatids, where reciprocal exchange of genetic material occurs, facilitated by the formation of recombination nodules on the synaptonemal complex. The result of these crossover events is an increased genetic variation within the gametes produced at the end of meiosis.
Crossover events are responsible for the unique combination of genetic information in the resulting gametes, fostering genetic diversity among offspring. Thus, by the end of the pachytene stage, the crucial genetic recombination process in meiosis has been completed, laying the groundwork for subsequent stages, including diplotene and diakinesis, where the synaptonemal complex degrades, and the chromosomes begin to pull apart, followed by metaphase I and subsequent steps that lead to the formation of haploid cells.