How do spindle fibres function during Anaphase I?

During Anaphase I of meiosis, spindle fibers play a crucial role by contracting to pull chromosome pairs apart. This phase is characterized by the separation of homologous chromosomes, which are pulled towards opposite poles of the cell. The spindle fibers, which are composed of microtubules, attach to the kinetochore regions of the chromosomes at their centromeres. When the spindle fibers contract, they generate a force that effectively moves each homologous chromosome in opposite directions, ensuring that each daughter cell will receive one complete set of chromosomes.

This action is vital for maintaining genetic diversity and reducing chromosome number by half, which is a key outcome of meiosis. The proper functioning of spindle fibers is essential for the accurate distribution of genetic material, and any errors during this process can lead to genetic disorders or aneuploidy.