Reared at 20°C or less Reared at temperatures above 30°C

environmental change, putting an affected child on a low-phenylalanine diet, prevents retardation.

These examples illustrate the point that genes and their products do not act in isolation; rather, they frequently interact with environmental factors. Occasionally, environmental factors alone can produce a phenotype that is the same as the phenotype produced by a genotype; this pheno-type is called a phenocopy. In fruit flies, for example, the autosomal recessive mutation eyeless produces greatly reduced eyes. The eyeless phenotype can also be produced by exposing the larvae of normal flies to sodium metaborate.

Was this article helpful?

0 0

Post a comment