HOMOLOGOUS RECOMBINATIONS IN TRANSGENIC MICE WITH GENE
OF NEOMYCINPHOSPHORYBOSYLTRANSFERASE
Ginkul L.B., Shvemberger I.N.
Institute of Cytology, Russian Academy of Sciences, St.Petersburg, Russia
The concept of genome stability is commonly accepted; due to this stability,
hereditability of signs is performed. However, recently, an increasing attention of many
geneticists has been paid to instability of genome. This problem is very important, as it
is essential to know forms and amount of such instability as well as its effect on
physiological processes and, of course, on heredity. At present, point mutations are
established to take place in genome more frequently than it was thought earlier. Recently
it has become evident that the majority of point mutations are neutral for life because
either their effect on cells is not significant or the cells-mutants are eliminated from an
organism by apoptosis. A great attention is paid to the role of micro- and mini-satellites,
of mobile gene elements in the genome stability, and of homologous DNA
recombinations in the normal cell functioning, in development of pathology, particularly
of malignant growth, and in evolution. To elucidate effects of the homologous DNA
recombination on the animal organism, we used transgenic mice carrying gene of
neomycinphosphoribosyltransferase (neo) with two deletions in the 3'- and 5'-sites of
gene. Homologous recombination was revealed in all 8 examined transgenic mice neo.
The set of tissues, in which the homologous DNA recombination of the gene neo was
found, differed in mice from different parents. At the same time, the set of such tissues
in F1, F2 mice — offsprings of one parent — coincided to a significant degree, which
indicates heredity of such recombination. This means that either efficiency of the
homologous DNA recombination of gene neo differed in different tissues or this
recombination occurred at different moments of tissue differentiation. Recombination of
the neo gene most likely took place at the period of embryogenesis and the subsequent
growth of organs. It is to be noted that the homologous recombination neo did not affect
the mice phenotype. This allows the conclusion to be made about the possible neutral
character of recombination processes in genome in nature. The fact that recombinations
occurred in different mice in different organs means that this process has a purely
stochastic character. The recombinations able to play a role in development of pathology
and in evolution.