The first principles of heredity; with 75 illustrations and diagrms . • DD D(R) D(R) RR Fig. 49.—Mendelism. (After Thomson.) Here DD stands for pure, or so-called extracted, domi-nants, RR for pure recessives, and D(R) for impuredominants. We see, then, that when two distinct varieties are crossed,where one is dominant with regard to a certain character,while the other is recessive, the first hybrid generation (F^)is an impure dominant. On interbreeding, the nextgeneration (Fo) can be divided into four parts—one puredominants, two impure dominants, and one pure impure dominants
The first principles of heredity; with 75 illustrations and diagrms . • DD D(R) D(R) RR Fig. 49.—Mendelism. (After Thomson.) Here DD stands for pure, or so-called extracted, domi-nants, RR for pure recessives, and D(R) for impuredominants. We see, then, that when two distinct varieties are crossed,where one is dominant with regard to a certain character,while the other is recessive, the first hybrid generation (F^)is an impure dominant. On interbreeding, the nextgeneration (Fo) can be divided into four parts—one puredominants, two impure dominants, and one pure impure dominants split up once more on furtherbreeding into the same proportions, while the pure domi-nants and recessives each time breed true for all successivegenerations. How can these Mendelian phenomena be accounted for ?Mendel himself explained them in a most ingenious, andyet at the same time very simple, manner. If of the two parent forms under consideration one parentD has the dominant quality d, while the other parent R hasthe recessive quality r, then the germ-cel
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1910
