Agro-Biotechnology: - The Greens | European Free Alliance

Technical problems | Cloned farm animals - a ‚killing application‘? | 19
in chromatin structure and/or gene expression. Miyashita et al. noted differences
in telomere lengths among cloned cattle derived from different cell
types. Moreover, X-chromosome inactivation may (mice) or may not (cattle) be
normal. Wrenzycki et al. noted aberrant expression of genes thought to be of
importance in stress adaptation, trophoblastic function, and DNA methylation
during preimplantation development in cloned bovine embryos. Yet, many
mice and other animals have survived to adulthood despite widespread gene
dysregulation, indicating that mammalian development may be rather tolerant
to epigenetic aberrations of the genome. The ultimate consequences of epigenetic
aberrations of the genome in cloned animals remain unclear but may
result in an early death.”
Epigenetic dysregulation is not the only possible reason for adverse effects in
next generations. Other possible reasons are disturbances on the level of DNA
possibly derived from the donor animals or caused by the SCNT process. FDA
(2008) mentions three examples:
“Three traits that may be genetically caused were identified (cryptorchidism 20
in three calves derived from the same cell line, parakeratosis 21 in one swine
clone, and sensitivity to endophyte 22 toxicity in two cattle clones). These may
pose health risks to the animals, and are certainly economically undesirable.”
So far it has been impossible to exclude risks for further generations. Where
unexpected effects occur in the following generations, they might cause
substantial damage because of the widespread use of single bulls for artificial
insemination. The Center for Food Safety criticises EFSA for disregarding studies
that show epigenetic effects in F1 generation of cloned animals and warns
of possible effects for further generations caused by mutations and epigenetic
effects (cited from EFSA 2008b):
“Any chromosomal instability and lack of maintenance of genetic integrity
(somatic mutations) in clones could have widespread consequences. Indeed,
a large proportion of these putative mutations would have a recessive effect,
meaning that they would be expressed, and therefore detected, only several
generations after their spread in the populations. The same is true for the
epigenetic status of live cloned animals.”
It has to be acknowledged that epigenetic disturbances once established and
spread through large animal populations have a huge potential for causing
extreme damage in animal food production and agriculture.
20 The testis do not descend but remain inside the body
21 Problem of the skin
22 funghal organism