In meiosis, how do the chromosomes "know" their homologue?

Question

In meiosis, how do the chromosomes "know" their homologue?

Answer 1

some chemical signal that they give off. it takes a long time though. that's why prophase I takes the longest time

Answer 2

Three main things:

Telomere clustering - Telomeres at the ends of chromosomes get close together (mechanism unknown at this time)

Nuclear oscillation - Oscillation of the microtubules in the nucleus causing movement of the chromosomes.

Recombination - Recognition of homologous sequences (acts as glue once two matching chromosomes happen to find each other).

Here is an abstract from a paper concerning the topic:

"Pairing of homologous chromosomes is important for homologous recombination and correct chromosome segregation during meiosis. It has been proposed that telomere clustering, nuclear oscillation, and recombination during meiotic prophase facilitate homologous chromosome pairing in fission yeast. Here we examined the contributions of these chromosomal events to homologous chromosome pairing, by directly observing the dynamics of chromosomal loci in living cells of fission yeast. Homologous loci exhibited a dynamic process of association and dissociation during the time course of meiotic prophase. Lack of nuclear oscillation reduced association frequency for both centromeric and arm regions of the chromosome. Lack of telomere clustering or recombination reduced association frequency at arm regions, but not significantly at centromeric regions. Our results indicate that homologous chromosomes are spatially aligned by oscillation of telomere-bundled chromosomes and physically linked by recombination at chromosome arm regions; this recombination is not required for association of homologous centromeres."