Researchers from Kumamoto University in Japan have revealed a potential genetic cause for infertility in a new study published in Developmental Cell.
The work, carried out in mice, reports the identification of a new gene, which appears to regulate the process of meiosis, a specialised form of cell division that occurs in the ovaries and testes, leading to the generation of gametes (eggs and sperm).
Most cells in the body replicate through a process of cell division called mitosis whereby a single cell doubles its genetic information and then divides equally to create two copies of the original cell. Meiosis takes this process a step further, proceeding to a second cell division, resulting in the generation of four cells that contain half the genetic material, so that upon fertilisation the new cell has one full set of chromosomes.
In the current study the team used a mouse model to identify the gene meiosin, which appears to drive meiosis. When inactivated the researchers observed a reduced or abnormal production of germ cells in both sexes.
The scientists also observed that meiosin is only expressed at certain times in the testis and ovary, when the switch from mitosis to meiosis is taking place, which makes it unique in comparison to other genes previously thought to regulate the process.
'Our work shows that the meiosin gene is the switch that turns on meiosis, the special type of cell division that creates eggs and sperm,' said Dr Kei-Ichiro Ishiguro lead author of the study.
When investigating further, the researchers revealed that meiosin itself switches on hundreds of other genes, many of which currently have unknown functions.
'We were quite surprised to find so many genes with undefined functions lying dormant in this study. We have high expectations that the processes involved in germ cell formation will be greatly clarified as the role each of these genes plays is discovered,' added Dr Ishiguro.
While meiosin is known to exist in humans, further work will be required to determine the exact role in human fertility.
The improper division of genetic material as a result of abnormal meiosis can result in miscarriages or chromosomal disorders. Although the research is at an early stage, the authors hope that the study will lead to a greater understanding of these issues.
'If it eventually becomes possible to control meiosis, the benefits would be far-reaching for reproductive medicine, agricultural production, and even assisting rare species reproduction,' Dr Ishiguro concluded.