| Popis: |
Reproduction by cloning can eliminate some of the problems inherent to sexual reproduction, but it creates others. The genetic heritage of nucleus donor cells and the genetic status of clones are not precisely known. Furthermore, reprogramming of the genome of nucleus donor cells by the ovocyte cytoplasm is often incomplete. Animals obtained through cloning are thus essentially genetically identical to their genitors, but they are often epigenetically modified, with unpredictable effects. Transgenesis results in most cases from the addition to a genome of one or more known genes. The direct and indirect effects of transgenesis cannot all be predicted. Specific confinement measures make it possible to raise animals in high-security conditions, preventing their dissemination in the human food chain, in animal feed or in the environment. The toxicity, allergenicity and infectiousness of cloned ortransgenic animals can be evaluated by means of tests. |
