Genetics / D.J. Cove.

  • Cove, D. J.
Date:
1971
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Genetics / D.J. Cove. Source: Wellcome Collection.

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    haploid organisms 11 of the gene in which mutation can occur to give the y allele. These new symbols are used in figure 5, which represents the cross between the yellow-conidiospored strain and the slow-growing strain sym¬ bolically. If the scheme represented in figure 5 is correct, it should be possible to take a yellow-spored slow-growing recombinant progeny strain and cross it either to the original wild type, or to one of the wild-type progeny and to obtain exactly the same classes of progeny in the same proportions as in the original cross. This cross would Ъе y sm x +, These are indeed the results obtained when such crosses are carried out. Aspergillus was not used in the original breeding experiments, which led to the conclusions about the nature of the mechanism of inheritance which have been drawn in this chapter. These original experiments, which were carried out by a monk, Gregor Mendel, working in Brno, in Czechoslovakia, used the garden pea, Pisum sativum. Mendel published his classic papers on inheritance in 1866, although his work attracted little attention until the beginning of this century. In them he proposed all the principles already mentioned in this chapter; particularly that no blending occurred for individual character differences, and that information for different characters could be distributed independently to the progeny. This was a very remarkable achievement, especially as the results which Mendel obtained with his breeding experiments using a ñowering plant were quite different from those which are obtained with Aspergillus. These results will be described in detail in the next chapter, which will also show how they can be reconciled with the results of breeding experiments with fungi.