Early embryonic development is controlled by the genome of both maternal and embryonic . Oocyte maturation , fertilization and the first cleavage divisions characterized by a lack of effective transcription , hence these processes are completely controlled by the factors of maternal origin . Persistence of maternal transcripts depends on the length of the poly (A ), which may be lengthening or shortening . Starting embryonic genome is species-specific and occurs after several cleavage divisions . It connects with the gradual disappearance of maternal mRNA.

The article discusses some methods for testing the ability of cancer cells to metastasize. A review of the most important methods for the study of this phenomenon both in vivo and in vitro.