A homolog is a chromosome that is physically and genetically identical to another chromosome with which it partners during meiosis.
The events of the meiotic prophase are accompanied by observable chromosomal alterations under the microscope.
During the early prophase, chromosomes condense and homologs relocate to locations close to one another in the nucleus.
Homolog Pairing:
In a process known as homolog pairing, the two homologs of each chromosome align in parallel.
The pairing of homologous chromosomes is essential for their reliable segregation during meiosis I, which underpins sexual reproduction.
In most eukaryotes, homolog pairing occurs only during the prophase of meiosis I and is followed by numerous exchanges of homologous chromatids, known as crossovers.
Crossovers generate chiasmata, which are stable interhomolog connectors essential for homolog bipolar orientation (orientation to opposing poles) during meiosis I.