Raju N B
Can J Genet Cytol. 1986 Dec;28(6):982-90. doi: 10.1139/g86-136.
Two nonallelic Four-spore mutants are known in which ascospore walls enclose the four immediate products of meiosis rather than the normal eight products of a postmeiotic mitosis. Expression depends on temperature. The Four-spore phenotype is expressed when the developing asci are subjected either to high temperatures (25-30 degrees C) for Fsp-1 or to low temperatures (15-20 degrees C) for Fsp-2. Heterozygous Fsp-1 X Fsp-1+ crosses make eight-spored asci at 15-20 degrees C but produce many four-spored asci at 25 degrees C and mostly four-spored asci at 30 degrees C. Homozygous Fsp-1 X Fsp-1 crosses respond similarly to increasing temperature but make 40-50% four-spored asci even at 20 degrees C. Heterozygous Fsp-2 X Fsp-2+ crosses produce almost exclusively four-spored asci at 15 degrees C but a mixture of four- and eight-spored asci at 20, 25, and 30 degrees C. Homozygous Fsp-2 X Fsp-2 crosses make all four-spored asci at 15 and 20 degrees C and a mixture of four- and eight-spored asci at 25 and 30 degrees C. When both Fsp-1 and Fsp-2 are present in a cross, either homozygous or heterozygous, no asci contain more than four ascospores at any temperature. Limited temperature-shift experiments with Fsp-1 and Fsp-2 show that the sensitive period for Four-spore expression is sometime after meiotic prophase, possibly at interphase II.
已知有两个非等位的四孢子突变体，在这些突变体中，子囊孢子壁包裹的是减数分裂的四个直接产物，而不是减数分裂后有丝分裂正常产生的八个产物。其表达取决于温度。对于Fsp - 1，当发育中的子囊在高温（25 - 30摄氏度）下时，会表现出四孢子表型；对于Fsp - 2，当发育中的子囊在低温（15 - 20摄氏度）下时，会表现出四孢子表型。杂合的Fsp - 1×Fsp - 1 +杂交组合在15 - 20摄氏度时产生八孢子子囊，但在25摄氏度时产生许多四孢子子囊，在30摄氏度时大多产生四孢子子囊。纯合的Fsp - 1×Fsp - 1杂交组合对温度升高的反应类似，但即使在20摄氏度时也会产生40 - 50%的四孢子子囊。杂合的Fsp - 2×Fsp - 2 +杂交组合在15摄氏度时几乎只产生四孢子子囊，但在20、25和30摄氏度时产生四孢子和八孢子子囊的混合物。纯合的Fsp - 2×Fsp - 2杂交组合在15和20摄氏度时产生的都是四孢子子囊，在25和30摄氏度时产生四孢子和八孢子子囊的混合物。当Fsp - 1和Fsp - 2同时存在于杂交组合中时，无论是纯合还是杂合，在任何温度下都没有子囊包含超过四个子囊孢子。对Fsp - 1和Fsp - 2进行的有限温度转换实验表明，四孢子表达的敏感期是在减数分裂前期之后的某个时间，可能是在减数第二次分裂间期。
