【摘要】 <正> 纤毛原生动物含有大核和小核。小核DNA分子量很大,组成染色体,在无性系生长期闯不产生RNA。小核在结合生殖时经过减数分裂而产生大核,大核只有无丝分裂,核内含400至10000碱基对DNA。这种DNA分子在结合生殖时通过大核发育而成。 Ammermann,Alonso et al,Golikova,最早发现腹毛类毛虫大核发育早期出现和双翅目幼虫相似的多线染色体。Kloetzel,Murti用电镜观察了游仆虫和棘尾虫的多线染色体,并指出多染色体在发育后期被纤维物质横贯形成染色体间带,进更多还原

【Abstract】 During macronuclear development in the early stages of Euplotes crassus, polytene chromosomes are formed in the anlage at 20 to 27 hours exconjugants. polytene chromosomes of E.crassus are very tightly packed with no band inter band structure.In Stylonychia mytilus, polytene chromosomes are formed in the macronucleus at 40 hours exconjugants. The chromosomes display band-inter band structure along their lengths. The polytene chromosomes arecomposed of fibrils and granules when viewed with electron microscope. As the anlage approaches the maximum degree of polytene, sheets of fibrous material appears in the nucleus, surrounding and transecting the polytene chromosome.更多还原