Polyphyletic allopolyploid origin ofRanunculus cantoniensis (4x) fromR. silerifolius (2x) ×R. chinensis (2x)

Both diploid and tetraploid experimental interspecific hybrids betweenRanunculus silerifolius (2x) andR. chinensis (2x) exhibit normal bivalent pairing. However, microspores of diploid hybrids do not undergo mitosis and their pollen grains are highly sterile, whereas tetraploid hybrids form good pollen grains after microspore division. Evidence is forwarded for the assumption thatR. cantoniensis (4x) has originated by hybridization between these two diploid parental species and by polyploidization of the diploid hybrids. Parallelisms between the different karyotypes ofR. cantoniensis (4x) andR. silerifolius (2x) suggest that the former is a species of polyphyletic origin.     

x,i(xq)—x染色体长臂等臂一例

刘X,女,14岁。因生长发育迟缓就诊。患 者是第3胎足月顺产,2岁始会走路及说简单 话语,7岁上小学,二年级时因全部课程不及 格,被迫退学。患者生后即生长发育缓慢,现可 从事一般家务劳动,无月经来潮。母孕期未接 触有害物质,无流产史,家族中无类似患者