For the first time , scientists have identify how the ovarian reserve , which underpins mammalian distaff fertility rate , is install . put out in the journalNature Communications , a novel study supply much - need insight into the molecular base of female reproductive health , in mice at least .

The “ ovarian reserve ” is essentially an indicator of the ovary ’s capacity to provide egg that could be fertilized and leave in a viable pregnancy . Specifically , it refers to the number of aboriginal follicle – follicles found in mammalian ovary which each contain an oocyte that subsequently modernise into an egg – that a person has . The number of primal follicles is finite in mammals – we are stick out with a certain amount and do n’t develop more – and , unfortunately , as we age the figure of follicles we have dwindles .

This trifle a massively important function in femalefertility , and yet comparatively niggling is be intimate about it .

“ Despite its profound importance , our savvy how the ovarian reserve is established and assert remains misfortunate , ” co - author Professor Satoshi Namekawa of the Department of Microbiology and Molecular Genetics at the University of California , Davis say in astatement .

But with this new bailiwick , that has now changed . The researchers have been able-bodied to define , in mice , specific epigenetic changes – reversible changes that affect gene expression but do n’t affect DNA sequence – which excuse the establishment of the substitute that has perplex scientists for so long .

And the real - earth implications of this could be immense , the authors say : “ Our subject field may give us the foundation to understand how female fertility is establish and maintained at the molecular level and why it wane with geezerhood , ” Namekawa bring .

Prior to the establishment of themammalian ovarian reserve , oocyte can pause a fundamental developmental process called reduction division . Meiosis fall out when eggs or spermatozoan cells separate and reduce their genic material so that each cellular telephone only has one copy of each chromosome . Avoiding this , oocyte can stay in an arrested state for decades , which we already get it on is what establishes the ovarian reticence and therefore defines the distaff reproductive lifespan . However , what we did n’t know until now is just how oocyte are capable to stay in this country for so long .

In a serial of mouse study , the team identify a central group of protein that supervise the developmental pause . Polycomb Repressive Complex 1 ( PRC1 ) mediates gene silencing and , the author reveal , is essential in establishing the arrest state . When PRC1 was mutated so that it no longer functioned , the ovarian reserve could not be established and mouse experienced premature ovary failure .

“ We show that a conditional PRC1 excision result in speedy depletion of follicles and sterility , ” state Namekawa . “ These termination powerfully entail PRC1 in the critical physical process of maintaining the epigenome of primordial follicle throughout the draw out arrest that can last up to 50 year in human . ”

We might in the end acknowledge a little more about the establishment of the ovarian reserve , but as for its internal workings , there are still enquiry to be answered :

“ Can we reveal a more elaborate mechanism of this process ? How can the ovarian reserve be maintained for decennium ? ” Namekawa asked . Watch this space .