Meiosis is a specialized cell division that enables sexually reproducing organisms to generate reproductive cells with reduced chromosome ploidy. Crossover recombination is normally essential for successful ploidy reduction during meiosis, as crossovers create attachments that orient homologous chromosomes and facilitate their subsequent segregation apart from one another on the spindle. Thus, the meiotic cell must ensure a sufficient number of recombination events repair as interhomolog crossovers (instead of non-crossovers). Many of the events that process meiotic DNA repair intermediates into interhomolog crossovers occur within the context of a meiosis-specific tripartite structure called the synaptonemal complex (SC), which assembles along lengthwise-aligned homologous chromosomes. Mutants missing building block components or regulators of SC assembly typically exhibit reduced or absent crossover recombination. In several organisms including budding yeast, crossovers specifically associated with SC are mediated by MutSg, a set of proteins related to the prokaryotic MutS family of mismatch repair enzymes. Despite the correlation between SC and crossover formation, the functional relationship between the SC structure, SC components, and MutSg crossover recombination has remained obscure. Our analysis of several budding yeast mutants demonstrates unequivocally that the SC structure is dispensable for MutSg crossover formation. First, through an interspecies complementation experiment we found that the crossover promoting activity of budding yeast SC component, Zip1, can be replaced by Kluyveromyces lactis Zip1, yet K. l. Zip1 does not assemble SC in S. cerevisiae cells. Second, we found that mutants missing either of the SC central element proteins - Ecm11 or Gmc2 - exhibit no deficit in, but rather an increase in, MutSg crossovers. We furthermore identified a non-null zip1 mutant that phenocopis ecm11 and gmc2 mutants: zip1-N1 mutant meiotic cells fail to assemble SC and exhibit an elevation in MutSg crossovers. Our studies reveal that the SC structure is built of two classes of components: Zip1 represents an SC component with genetically separable activities that promote crossover recombination and SC assembly, while the central element proteins Ecm11 and Gmc2 solely function in SC assembly. Interestingly, we discovered that ecm11 and gmc2 mutants exhibit a mismatch repair defect during meiosis. The mismatch repair activity associated with SC central element proteins does not require Ecm11 SUMOylation, suggesting that it is independent of the SC structure per se. Thus both SC transverse filaments and central element components collaborate in building SC structure that attenuates crossover recombination, while these proteins act independently of the SC structure to positively influence recombination in distinct ways.