[Two doses of the paternal Tme gene do not compensate for the lethality of the Thp deletion in mice].

The hairpin-tail (Thp) deletion in chromosome 17 is lethal when inherited from the mother. Heterozygotes with this deletion, paternal in origin, are viable. The Thp maternal effect is related to a deficiency of Tme gene located in the Thp deleted region. Herein, the viability of mice with tertiary trisomy of chromosome 17Ts(17(16))43H with different doses of the paternal and maternal Tme alleles is analysed. It is demonstrated that the presence of an additional copy of the region with Tme in the female gamete entirely compensates Thp maternal lethality. We failed to compensate the absence of the Tme gene in the chromosome of maternal origin with a double dose of Tme derived from the father. Thus, evidence was obtained indicating that there are sharp differences between the activities of the paternal and maternal alleles of the Tme gene, due to chromosome imprinting.