14.1Introduction Bivalent is the structure containing all four chromatids(two representing each homologue )at the start of meiosis Breakage and reunion describes the mode of genetic recombination, in which two dna duplex molecules are broken at corresponding points and then rejoined crosswise(involving formation of a length of heteroduplex dNa around the site of joining) Site-specific recombination occurs between two specific(not necessarily homologous)sequences, as in phage integration/excision or resolutionof cointegrate structures during transposition Synapsis describes the association of the two pairs of sister chromatids representing homologous chromosomes that occurs at the start of meiosis resulting structure is called a bivalent Synaptonemal complex describes the morphological structure of synapsed chromosomes Transposition refers to the movement of a transposon to a new site in the genome 消当Bivalent is the structure containing all four chromatids (two representing each homologue) at the start of meiosis. Breakage and reunion describes the mode of genetic recombination, in which two DNA duplex molecules are broken at corresponding points and then rejoined crosswise (involving formation of a length of heteroduplex DNA around the site of joining). Site-specific recombination occurs between two specific (not necessarily homologous) sequences, as in phage integration/excision or resolution of cointegrate structures during transposition. Synapsis describes the association of the two pairs of sister chromatids representing homologous chromosomes that occurs at the start of meiosis; resulting structure is called a bivalent. Synaptonemal complex describes the morphological structure of synapsed chromosomes. Transposition refers to the movement of a transposon to a new site in the genome. 14.1 Introduction