Final answer:
In yeast zip1 and zip2 mutants, correct pairing still occurs, axial associations are formed, but no synaptonemal complexes are formed, these complexes are crucial for genetic recombination during meiosis.
Step-by-step explanation:
Synaptonemal complexes are protein structures that hold homologous chromosomes together during meiosis, facilitating genetic recombination. They are important for accurate chromosome segregation and the generation of genetic diversity.
Without synaptonemal complexes, the process of crossing over, where genetic material is exchanged between homologous chromosomes, cannot occur effectively. This may lead to defects in chromosome segregation and reduced genetic diversity in the resulting gametes.
So therefore in yeast zip1 and zip2 mutants, correct pairing still occurs between homologous chromosomes, and axial associations are still formed. However, these mutants fail to form synaptonemal complexes.