Transgenerational Effects of Modifications of the Embryonic Environment in Quail

Epigenetic phenomena, such as DNA methylation, which participate to the regulation of gene expression, can influence phenotypes. The influence of the embryonic environment on the adult phenotype, through epigenetic marks, has been observed in numerous cases. Recent studies show that epigenetic information may be transmitted across generations.

Our aim was to observe if a modification of the quail embryonic environment would have transgenerational effects. We observed phenotypic differences in the third generation between two lines, obtained after treating (Epi+) or not treating (Epi-) eggs from a common set of founders G0, by injection of genistein. We used genistein as it is known to interfere with the epigenome, especially with DNA methylation. A "mirror" device was set, with parallel genealogies in each line, to minimize the putative influence of genetics on trait variability. After 3 generations without any further treatment, a significant difference in sexual maturity was observed between the lines, with the Epi+ G3 birds starting laying eggs later. A significant interaction between line and sex was observed for 3-week body weight and for eye temperature. Two behavioral traits in the G3 were also significantly affected by the initial treatment. Global methylation analyses are ongoing.

These observations demonstrate the impact of a modification of the founders' embryonic environment on the phenotype of quails, three generations later. While genetic variability cannot definitely be ruled out, the mirror animal device should have minimized its effects, and observed differences in  the G3 may be attributed, at least partly, to transgenerational epigenetic phenomena.