The chromosomal pair which contains the maternal as well as the paternal chromatid of the same length and gene position, and are joined by the centromere is referred to as a homologous chromosome.
These are the sites where crossing over takes place b/w non-sister chromatids of the homologous chromosomes.
Prophase I of meiosis I is the unique phase that involves the recombination of genetic material b/w homologous chromosomes.
This occurs in the pachytene stage where non-sister chromatids of the homologous chromosomes cross over & exchange of genetic material takes place.
Recombination nodules are placed at which the non-sister chromatids crossover.
For example, the two copies of Chromosome 1 in a cell are referred to as homologous chromosomes.