Experimental embryology of mammals at the Jastrzebiec Institute of Genetics and Animal Breeding.

The research article discusses the advancements made by the Department of Experimental Embryology at the Jastrzebiec Institute of Genetics and Animal Breeding in the field of embryo biotechnology. Their work includes experimentation with animal embryos through cloning, freezing, and various methods of transfer resulting in the creation of chimeras and new creatures.

History and Key Achievements

• The Laboratory of Embryo Biotechnology, predecessor of the Department of Experimental Embryology, was established by Dr. Maria Czlonkowska. Notably during her leadership, the laboratory made significant strides in embryo biotechnology such as the successful international transfer of frozen equine embryos and the generation of a sheep-goat chimera which survived for a decade.

Research and Experiments in the 1990s

• During this period, the Department was able to produce advanced fetuses of mice by reconstructing enucleated oocytes with embryonic stem (ES) cells.
• They also created mice entirely from ES cells by replacing the inner cell mass with ES cells.
• Attempts to obtain ES cells in sheep led to the development of embryo-derived epithelioid cell lines from Polish Heatherhead and Polish Merino breeds. These cells produced visible chimeras when injected into a blastocyst.

Cloning and Re-cloning Experiments

• Successful re-cloning was achieved from 8-cell rabbit embryos, and healthy animals were born from the third generation of cloned embryos.
• Additionally, mice were born after the transfer of 8-cell embryonic nuclei into selectively enucleated zygotes.
• In a more complex experiment, mouse blastocysts were produced from selectively enucleated germinal vesicle oocytes surrounded by follicular cells, after reconstructing these with 2-cell nuclei and subsequently activating them.

Chimeras and Conservation Efforts

• Embryonic-somatic chimeras were created after transferring fetal fibroblasts into 8-cell mouse embryos and into sheep morulae and blastocysts.
• The Department doesn’t only focus on cloning and producing chimeras. They also regularly carry out applications like in vitro production of bovine embryos from slaughterhouse oocytes, cryopreservation of oocytes and embryos of various animals, and even banking of somatic cells from endangered mammalian species, especially those belonging to the Cervidae family, contributing significantly to conservation efforts.