#synapsis

• Allosyndesis — A cytogenetic phenomenon or structural process consisting of the pairing (synapsis) during meiosis of non-homologous chromosomes originating from different parents or distinct species within a hybrid or allopolyploid organism. This type of atypical chromosomal association differs structurally from autosynapsis and plays an essential role in analyzing genomic reconfiguration and the degree of phylogenetic relationship between taxa.
• Amphitene — A transient stage in the prophase of the first meiotic division, occurring between leptotene and pachytene, synonymous with zygotene, during which homologous chromosomes begin to align and pair up through synapsis. In this structural phase, the chromatid threads often present a characteristic bouquet arrangement, with one end thickened and the other thin during the pairing process.
• Asynapsis — A structural biological phenomenon consisting of the absence or failure of alignment and pairing of homologous chromosomes during the prophase of the first meiotic division. This cellular structural anomaly prevents the formation of bivalents and the unfolding of the crossing-over process, frequently leading to aberrant chromosomal segregation, the formation of non-viable gametes, or the sterility of the affected organism.