Researchers, led by an Indian-origin scientist, have identified genes which help female mice and some other mammals delay the onset of pregnancy.
Unlike in humans, the remarkable ability, known as embryonic diapause, is a temporary state of suspended animation that occurs when environmental conditions are not favourable to the survival of the mother and the newborn.
A new study, published in the journal Open Biology, reveals the molecular mechanism responsible for pausing and resuming a pregnancy.
After an egg is fertilised, it forms a cluster of cells known as a blastocyst, which implants in the wall of the mother's uterus, 'LiveScience' reported.
However, in diapause, the blastocyst is prevented from implanting and preserved in an dormant state until pregnancy resumes. How this process occurred was a mystery till now.
Researcher Sudhansu Dey, from Cincinnati Children's Research Foundation, and colleagues were studying the process of embryo implantation in mice when they noticed that a gene called MSX1 was very active just before implantation.
They began to suspect that it might play a role in diapause, Dey said.
Researchers used hormones to induce pregnancy delays in mice, mink and Tammar wallabies to investigate further. During this delayed state, Dey's team measured how active the MSX1 gene and other related genes were in generating protein-making instructions.
They imaged tissue from the animals to see where the gene was active. Finally, they tested whether these genes were being made into proteins.
Researchers found that the MSX genes were more active when pregnancies were delayed, and found this was true for all three animals.
The results are very exciting - they show that MSX genes, which are part of an ancient family of genes, have been preserved over much of evolutionary time, and play an important role in delaying pregnancy under harsh conditions, Dey said.
Dey wants to know whether the same genes may enable delayed pregnancies in other animals and ultimately, a deeper understanding of diapause could have implications for humans.
"If we keep MSX1 maintained at higher levels in human [women], maybe we can extend the receptive phase" for fertilisation, he said, though he added that such an extension may be many years away," he said.
