Department of Biology, University of Essex, Colchester, United Kingdom.
Genetics. 1983 Mar;103(3):409-28. doi: 10.1093/genetics/103.3.409.
Four-point mitochondrial crosses were conducted in heterokaryons of Aspergillus nidulans. The mutations used were (oliA1), conferring resistance to oligomycin, (camA112), conferring resistance to chloramphenicol; (cs-67), conferring cold-sensitivity, and ( sumD16), a suppressor of (cs-67). Initially, the crosses were conducted by observing the segregation of extranuclear markers in heterokaryotic sectors emerging from the original point of heterokaryosis. This showed that (camA112), (cs-67) and (sumD16) were linked but were probably all unlinked to (oliA1). Second, four-point crosses were conducted using a double marker selection technique, in which (camA112 ) and (oliA1) were always set in repulsion and the frequency of the phenotypes produced by the segregation of the mutant and wild-type alleles of (cs-67) and (sumD) were observed in (camA112 oliA1) recombinants. From these results we concluded that (camA112 ), (cs-67) and (sumD16) were linked and probably mapped in the order given. It was observed that the two nuclear types of conidia from a heterokaryon often had a dissimilar frequency distribution of the segregants of a mitochondrial cross.
在构巢曲霉的异核体中进行了四点线粒体杂交。所用的突变体是（oliA1），对寡霉素有抗性；（camA112），对氯霉素有抗性；（cs-67），对冷敏感；和（sumD16），对（cs-67）的抑制。最初，通过观察异核体扇形区中外核标记的分离来进行杂交，这表明（camA112）、（cs-67）和（sumD16）是连锁的，但可能都与（oliA1）不连锁。其次，使用双标记选择技术进行四点杂交，其中（camA112）和（oliA1）总是在排斥状态，观察到（camA112 oliA1）重组体中（cs-67）和（sumD）的突变型和野生型等位基因分离产生的表型的频率。从这些结果我们得出结论，（camA112）、（cs-67）和（sumD16）是连锁的，可能按照给定的顺序进行定位。观察到异核体的两个核型的分生孢子通常对线粒体杂交的分离子有不同的频率分布。
