1a

Updated: May 18, 2025

Both of the pure groups have therefore reappeared in the same numbers. Calling A the specimens with the pure active mark, L those with the latent mark, and H the hybrids, these proportions may be expressed as follows: 1A+2H+1L. This simple law for the constitution of the second generation of varietal hybrids with a single differentiating mark in their parents is called the law of Mendel.

Hugo de Vries - Species and Varieties, Their Origin by Mutation

In November I was living in Fraulein Dahlweiner's PENSION, 1a, Karlstrasse; but my working quarters were a mile from there, in the house of a widow who supported herself by taking lodgers. She and her two young children used to drop in every morning and talk German to me by request.

Mark Twain - Life on the Mississippi

These considerations lead us to the following form of Mendel's, P + O = 1/4 Active or 1A, P + O' > = 1/2 Hybrid or 2 H, P' + O P' + O' = 1/4 Latent or 1 L, Which is evidently the same as Mendel's empirical law given above. To give the proof of these assumptions Mendel has devised a very simple crossing experiment, which he has effected with his varieties of peas.

Hugo de Vries - Species and Varieties, Their Origin by Mutation