The Influence of the Environment on the Size of Expected Classes

Abstract

In crosses in which rudimentary wings are involved, it has been apparent, since this race was first bred, that the classes containing rudimentary wings often run far behind expectation. The experiments made clear that the character rudimentary wings is a Mendelian recessive and is sex-linked. The deficiencies that appeared were assigned to viability of these flies. We have found meanwhile for other stocks that by breeding pairs of flies in large bottles, with an abundance of food, kept in good condition, there was a very marked increase in number of those classes that are deficient in number if many flies are bred in small bottles, or even in large bottles if so many parents are used that crowding of the larvae takes place. It was determined, therefore, to repeat the experiments with rudimentary wings under the most favorable conditions that our experience had made known to us. In order to avoid the possible criticism that the stock might have changed, a control culture en masse was again made in which crowding took place.