Serial Transplantation of Embryonic Nuclei

Abstract

Over the past many years genetical research has revealed large numbers of gene effects on cell differentiation. These are usually effects on the final phases of differentiation, but may also be manifested at early developmental stages (Glu-ecksohn-Waelsch, 1954; Hadorn, 1948, 1956; Poulson, 1945; and others). In principle, the anal-ysis of these effects depends upon the permanent alteration or deletion of a chromosome segment, and the subsequent detection of a change in (lifter-entiation--usually a deficiency. The evidence so obtained permits the conclusion that a particular gene or gene set is required for a particular type of differentiation to proceed normally. However, in general it leaves unanswered the questions