The synaptonemal complex is a protein structure that forms between homologous chromosomes during meiosis, facilitating chromosome pairing and recombination. This complex, characterized by a tripartite structure, was first described in the 1950s and comprises specific proteins such as SC protein-1, SC protein-2, and SC protein-3. The process of homologous chromosomes pairing is known as synapsis, occurring early in the first nuclear division of meiosis.

1. SYNAPTONEMAL COMPLEX

2. SYNAPTONEMAL COMPLEX
 The synaptonemal complex (SC) is a protein structure that
forms between homologous chromosomes (two pairs of sister
chromatids) during meiosis and is thought to mediate
chromosome pairing, synapsis, and recombination.
 The paired homologous chromosomes are joined by a protein
containing frame work called Synaptonemal complex.

3. Schematic of the synaptonemal complex at
different stages during Prophase I

4. Synapsis
 The 1st unique feature of meiosis happens early during
the first nuclear division.
 Following chromosome replication, homologous
chromosomes, or homologues pair all along their length.
 The process of forming these complexes of homologous
chromosomes is called synapsis

5. SYNAPTONEMAL COMPLEX
 The synaptonemal complex was described by Montrose
J. Moses in 1956 in primary spermatocytes of crayfish
and by D. Fawcett in spermatocytes of pigeon, cat and
man.
 The synaptonemal complex is a tripartite structure
consisting of two parallel lateral regions and a central
element.
 Three specific components of the synaptonemal
complex have been characterized: SC protein-1 (SYCP1),
SC protein-2 (SYCP2), and SC protein-3 (SYCP3).

7. A MATURE SYNAPTONEMAL COMPLEX