Gene that is responsible for a woman's maternal feelings towards her children has been discovered by researchers.
The researchers found that mice engineered to suppress the gene spent less time licking, nursing and retrieving their pups compared with a control group.
According to the scientists, the findings suggest the single gene could be responsible for motivating mothers to protect, feed and raise their young, the Telegraph reported.
Previous studies have found that a brain region called the medial preoptic area controls aggression, sexual receptivity and maternal care in mice.
But the chemical mechanisms, which influence these behaviours, have remained largely unclear.
Earlier research has established that nerve cells react to oestrogen, the female sex hormone, and contain high levels of oestrogen receptor alpha, a chemical linked to maternal care and sexual behaviour.
In the new study, scientists artificially lowered the levels of the chemical in the medial preoptic area of female mice, to examine how they functioned without it.
They found that the mice spent less time caring for their pups but that their levels of aggression remained unchanged.
"The main finding of this paper is manipulation of a specific gene in a specific group of neurons (nerve cells) can drastically alter the expression of a complete, biologically crucial behaviour," said Dr Ana Ribiero, who led the study.
The effects were "remarkably specific" to maternal care because even related behaviours, such as aggression, remained unchanged, she added.
The results were published in the Proceedings of the National Academy of Sciences.