During meiosis, synapsis (the pairing of homologous chromosomes) ordinarily precedes genetic recombination. In the knockout mice, meiotic chromosome synapsis is defective. In female "Drosophila melanogaster" fruit flies, meiotic chromosome synapsis occurs in the absence of recombination. In mammals, surveillance mechanisms remove meiotic cells in which chromosome synapsis is defective. In mammals, surveillance mechanisms remove meiotic cells in which synapsis is defective. I of meiosis during a process called synapsis. During synapsis, genetic recombination usually occurs. The process of pairing the homologous chromosomes is called synapsis. Meiotic recombination is also unnecessary for homologous chromosome synapsis in the nematode "Caenorhabditis elegans". The process of alignment of paired homologous chromosomes is called synapsis (see Synapsis). PARP1 may function as a synapsis factor in alternative non-homologous end joining. This is followed by synapsis, i.e. bringing the sites together to form the synaptic complex. This synapsis on the first structure discussed, the extrafusal fibers of the muscle spindle. Synapsis of the chromosomes in prophase is achieved at this stage.