CRYOBANKING OF SOMATIC CELLS IN CONSERVATION OF ANIMAL GENETIC RESOURCES: PROSPECTS AND SUCCESSES (review)

Abstract

A b s t r a c tExtinction of many species is irreversible and is a part of the natural evolution, but human activities have influenced this process, making it much faster comparing to speciation. According to FAO, approximately 20 % of the breeds of cattle, goats, pigs, horses and poultry in the world are currently at risk of disappearance, many have died in the past few years, as a result their genetic characteristics lost forever. The role of banks in the management of genetic resources and the conservation of endangered species is particularly noticeable in the last decade. Most cryobanks focus on the cryopreservation of gametes (primarily sperm) and embryos. Their main goal is to produce offspring using reproductive technologies, which include artificial insemination, in vitro fertilization and embryo transfer. The discovery of the phenomenon of reprogramming somatic cell nuclear allowed expanding the range of forms of biological material in programs for cryopreservation. Creating cryobanks of somatic cells as donors of nuclei for cloning considered an auxiliary instrument for the preservation and improvement of the gene pool of farm animals and poultry. To obtain viable cryopreserved cell lines very small amount of biopsy material, including that of dead animals, is sufficient, but such lines contain the complete genome and proteome. In contrast to germ cells, embryos and generative tissues, the cryopreserved somatic cells after repeated thawing are capable to regenerate, i.e. almost infinitely may serve as a source of biomaterial for use in assisted reproductive technologies and biological research, including retrospective reconstruction. Furthermore, due to the small size the somatic cells are more resistant to cryopreservation. This review also provides a brief description of the principles and history of cloning. The advantages of the use of different cell types as karyoplasts are discussed. In particular, almost all types of cells (e.g. embryonic cells, mammary cells, cumulus, granulosa, oviduct, liver, fibroblasts, white blood cells and embryonic stem cells) can be used for the production of cloned animals, but the cloning efficiency depends significantly on the type of cells. Aiming embryo development and birth of live offspring, the fetal fibroblasts as donors of nuclear material for cloning are most effective. Alternatively, the stem cells may be a source of the nuclei. Stem or progenitor cells (i.e., stem, determined to differentiate in specific type cells) are easier reprogrammed than terminally differentiated cells. Also when stem cells nuclei are used as karyoplasts the number of cloned embryos significantly increased. The advances in interspecific cloning as a strategy for restoration of rare and endangered species are discussed. Numerous examples show that somatic cells can be considered the most promising material for the recovery of animal genetic resources of different types. Particularly from 1997 to 2012 using the differentiated somatic cells domestic and wild animals of different specie...

IN VITRO PRODUCTION OF INTERSPECIES HYBRID EMBRYOS OF CATTLE (Bos taurus) AND WISENT (Bison bonasus)

“…Low genetic variability is one of the main threats to the long-term maintenance of the species. Assisted reproductive technology such as production of in vitro embryos using oocytes of domestic cattle and wisent semen will not only help to maintain the existing genetic resources of the species, but also to involve this species in basic research on the physiology of development and use in creations of new bred forms [2][3][4].…”

“…Low genetic variability is one of the main threats to the long-term maintenance of the species. Assisted reproductive technology such as production of in vitro embryos using oocytes of domestic cattle and wisent semen will not only help to maintain the existing genetic resources of the species, but also to involve this species in basic research on the physiology of development and use in creations of new bred forms [2][3][4].Cow oocytes are a universal object for interspecific hybridization. In publications, there is evidence of their in vitro fertilization using semen of gaur [5], antelope [6], horse [7], sheep [8], and donkey [9].…”

Biobanking and use of gonadal tissues - a promising strategy for conserving wildlife from the Caatinga biome

“…Although the extinction of species is an irreversible process and is the result of natural evolution, anthropogenic activities have considerably accelerated extinctions of many species ( Singina et al, 2014 ). According to data from the Red List of the International Union for Conservation of Nature, of a total of 138,300 species surveyed, more than 38,500 species are threatened with extinction, 26% of which are mammals ( IUCN, 2022 ).…”

“…In the current situation, zoos, universities, research centers and other conservation institutions have become important organizations for the development of conservation strategies for wildlife species ( Pizzutto et al, 2021 , Stadtländer, 2022 ). Among such important conservation strategies, the role of Biological Resource Banks (BRB) in the establishment of genetic resources and the conservation of endangered species is particularly evident in the last decade ( Singina et al, 2014 ; Holt and Comizzoli, 2021 ).…”

Biotechnological bases of the development of cloned pig embryos

“…In practice, this was implemented in June 1996 by a group of Scottish researchers led by Ian Wilmut, who reported the birth of the first cloned mammal (Dolly the sheep) with hereditary material identical to another adult animal, which was produced using differentiated cells (breast epithelium) (Wilmut et al, 1997). The serious interest of the scientific community, caused by the revolutionary breakthrough in this field of reproductive technologies, has led to the cloning of more than 20 mammalian species (Singina et al, 2014).…”