Yves Delage (1854-1920) as a forerunner of modern nuclear transfer experiments

Abstract

It is generally considered that animal cloning by nuclear transfer originated in proposals made by Hans Spemann (1936), following his experiments on delayed nucleation in the newt egg, which were preceded by similar attempts using the sea-urchin egg (Loeb, 1894). Briggs and King (1952) were the first to succeed in transplanting blastula and gastrula nuclei into the enucleated frog egg and in obtaining a significant number of normal tadpoles by means of this technique. We present evidence that much earlier (1895) Yves Delage (1854-1920), a French biologist, had clearly formulated the same experimental project of nuclear transfer, as a means to test Weismann's theory of cell differentiation during embryonic development. This was also Spemann's motivation. Both Delage and Spemann were aware of Loeb's experiments (1894), in which delayed nucleation in the sea-urchin egg was found to result in twin larvae. It is difficult to decide whether Delage's project was influenced by Loeb's findings. On the other hand, it seems that Spemann was not aware of Delage's proposal, since he did not express his own ideas on extended nuclear transfer before 1936. Finally, neither Delage nor Spemann imagined that nuclear transfer could be a means of obtaining groups of genetically identical animals (reproductive cloning). KEY WORDS: nuclear transfer, cloning, Delage, SpemannAlthough it is commonly believed that Hans Spemann, in the early decades of the 20 th century, pioneered the ideas of nuclear transplantation and reproductive cloning, a French biologist, Yves Delage (1854-1920), had proposed much earlier (1895) the concept of nuclear equivalence and suggested experiments of nuclear transfer.

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“…Somatic cell nuclear transfer (SCNT) is a valuable tool for examining the role of genetic changes and the reversibility of epigenetic marks during cell differentiation (Beetschen and Fischer, 2004). However, one serious issue with this technology is the low embryonic developmental rate, which has been largely attributed to the abnormal epigenetic status of the transplanted nuclei that have been derived from somatic cells (Ogura et al, 2013).…”

Somatic cell nuclear reprogramming of mouse oocytes endures beyond reproductive decline

“…While processing of the sperm genome in the ooplasm is the product of an evolutionary path aimed at reproduction, somatic reprogramming is an experimental procedure developed in the past decades to test the role of genetic changes and the reversibility of epigenetic marks during cell differentiation (Beetschen & Fischer, 2004). Although fertilization is reported to be negatively affected by maternal aging (Miao et al.…”

Somatic cell nuclear transfer: origins, the present position and future opportunities

“…This ability was shown first in sea urchin by Dreisch (1891 described in [2]). In subsequent experiments, similar observations were made in salamander by Spemann [3], ungulates by Willadsen [4] and mice by Rossant [5].…”

“…The nucleated segment of the embryo was allowed to divide several times before the ligature was loosened in order to allow one nucleus to move into the anucleated fragment of cytoplasm which had not divided. Ultimately, the two sections of the embryo each gave rise to a normal salamander showing that the nucleus that had divided several times before release into the anucleate fragment had not lost key regulatory factors, at least during that early stage of development (described in [2]). A few years later, he was the first person to describe what we would now recognize as nuclear transfer, describing it as a 'fantastical experiment' [3].…”