每一个中期染色体均由两条染色单体构成，两条染色单体通过何种结构彼此相连

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SQL Error: select id,body,options from ***_enewstiku where sourceid='24545' and id < 2107704 and id<>'2107704' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='24545' and id > 2107704 and id<>'2107704' order by id asc limit 5