遗传分析是本科遗传学教学的重要内容,四分子分析是真菌类遗传分析的独特方式,其中的粗糙脉孢菌顺序四分子分析不仅可以研究基因与着丝粒间的重组、基因间的重组,而且还可以精细研究同源染色体非姊妹染色单体之间的交换形式,是深入理解交换重组分子机制的重要遗传学研究材料。对此,教材中已有详尽的介绍。美中不足的是,中外教科书和相关专业期刊中缺乏对顺序四分子两基因连锁分析中7种基本子囊型归纳方法的具体介绍,令相关内容的学习留下疑惑。本文从顺序四分子两基因连锁遗传分析过程中涉及的3种四分子类型(PD、NPD和T)与两基因4种分离时期组合(Ⅰ Ⅰ, Ⅱ Ⅱ, Ⅰ Ⅱ, Ⅱ Ⅰ)的相互关系入手,设计表格,直观展现了二者的12种可能组合结果(3×4=12),并应用直观的对错符号(√、×),同时结合表后的3项分析,排除了其中的5种组合形式,最终归纳得到7种基本子囊型。本文提供了7种基本子囊型具体的归纳分析方法,解决了相关教学内容的论述不足问题,以期为真菌类顺序四分子遗传分析的教学提供帮助。

Genetic analysis is an important part of undergraduate genetics teaching and tetrad analysis is unique and integral for genetic analysis of fungi. The ordered tetrad in Neurospora is an important material for genetic analysis, which can not only be used to study recombination between genes and centromeres, but also between genes themselves, as well as study the fine cross patterns between non-sister chromatids of homologous chromosomes. However, in textbooks and related professional journals, there is a lack of specific introduction to the induction methods of the seven basic class asci used in two genes analysis. In the present paper, we designed a table presenting the correlation between the three tetrad types (PD, NPD, T) and the four segregation pattern groups (Ⅰ Ⅰ, Ⅱ Ⅱ, Ⅰ Ⅱ, Ⅱ Ⅰ) to visually show the 12 possible combinations (3×4=12). Then five of them were excluded through the "×" symbol and in addition with three comments attached with the table, thus finally we obtained seven basic ascus types. We hope that this analytical method can assist the teaching of ordered tetrad analysis in Neurospora.