Among the human genome, only 2% is composed of protein-coding genes, while 98-99% constitutes a non-coding genome. These non-coding genomes produce RNA molecules, which regulate the function of the entire genome. However not much is known about these non-coding genomes during early embryonic development in humans.

The Early-Stage Study

“For the first time, we have identified short non-coding RNA molecules in ova at different stages of maturity, in fertilised ova and in early embryos with the help of sequencing, as well as determined their editing on the molecular level in embryos. This is an important milestone on the path to a better understanding of embryonic development,” says Sanna Vuoristo, Ph.D., from the University of Helsinki, who heads the embryo research group.

It was found that most of the short RNA molecules in human ova belong to a class of molecules that were identified only recently in the ova of humans and primates. These molecules are found in the ovum and are not found in mice, which are used as model animals.

As the fertilized ovum develops and the genome of the embryo is activated, the number of oocyte-specific piRNA molecules drops dramatically and the share of the better-known micro-RNA (miRNA) molecules in the embryo increases.

“It’s extremely valuable that individuals and couples who have received infertility treatment have handed over samples for research purposes. It’s a precondition for conducting embryo research,” says Vuoristo.

This information thereby gained in the study from early stages of development (from human ova and embryos) helps to understand the problems occurring during pregnancy and thereby develop increasingly effective infertility treatments.

Source: Medindia