Tug-of-War Among Fetal Genes

Tug-of-war between father and mother's genes for both the sexes begin in the womb as the fetus utilizes a key signal to control its supply of nutrients from the placenta as per a study at the University of Cambridge, published in Developmental Cell.

Generally, the fetus receives its nourishment through placental (specialized organ that contains cells from both baby and mother) blood vessels. However, nearly 10% to 15% of babies have poor growth in the womb, commonly due to reduced growth of blood vessels in the placenta.

‘Tug-of-war between father and mother�s genes for both the sexes begin in the womb as the fetus utilizes a key signal to control its supply of nutrients from the placenta (the specialized organ that contains cells from both baby and mother).’

The study was carried out in mice to underline the signals responsible for poor intrauterine (inside the womb) growth in some babies.

Tug-of-War among Genes

It was found that the fetus sends a signal known as IGF2 that reaches the placenta through the umbilical cord. This signal is vital for deciding the growth of the placenta and its subsequent effects on nutrition.

"We've known for some time that IGF2 promotes the growth of the organs where it is produced. In this study, we've shown that IGF2 also acts like a classical hormone – it's produced by the fetus, goes into the fetal blood, through the umbilical cord and to the placenta, where it acts," says Dr. Ionel Sandovici, the paper's first author.

In addition, the team also found that the response to IGF2 in the blood vessels of the placenta is mediated by another protein, called IGF2R (both IGF2 and IGF2R genes being �imprinted' by molecular switches of both parental genes).

"In our study, the father's gene drives the fetus's demands for larger blood vessels and more nutrients, while the mother's gene in the placenta tries to control how much nourishment she provides. There's a tug-of-war taking place, a battle of the sexes at the level of the genome," says lead author Dr. Miguel Const�ncia.

Source: Medindia