生物体可遗传的变异的来源主要有（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='31889' and id < 2549292 and id<>'2549292' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='31889' and id > 2549292 and id<>'2549292' order by id asc limit 5