May 25, 2012
Study Finds Male Fertility Genes
Connie K. Ho for RedOrbit.com
A new report published in the American Journal of Human Genetics (AJHG) states that previously undiscovered male fertility genes were identified and the new findings provide more information regarding human production.
The study, conducted by University of Chicago researchers, hopes to shine some light on the issue of male infertility.
Much of the research on fertility has looked at studies dealing with infertile participants. Likewise, it is thought that a certain stigma is attached to the subject of infertility because there isn´t enough knowledge regarding the scientific causes of male infertility. As such, almost a quarter of infertility cases are unexplained.
Non-genetic factors, including alcohol and tobacco use, particular medications, and disease history, are also though to affect infertility.
"Such studies have not been able to identify genes or pathways contributing to variation in natural human fertility," commented Carole Ober, the lead author of the study, in a prepared statement.
Ober´s past research has focused on finding genes that impact complex phenotypes to bring more understanding to evolutionary history and how the variations in genes can influence their functions. Besides the issue of fertility, her lab has examined phenotypes that are linked to common diseases. The studies on common diseases have highlighted phenotypes related to asthma and heart disease.
For this project, Ober and GÃ¼lÃ¼m Kosova, a graduate student at the University of Chicago, studied the Hutterites, a founder population. The Hutterites are a branch of Anabaptists that keep to specific religious and social beliefs.
“The Hutterite environment is so remarkably uniform,” Ober said in a University of Chicago article “Medicine on the Midway” when addressing the culture of sharing food and goods among the Hutterites.
The experiment was a genome-wide association study of family size and birth rate, which are two traits of fertility, in a total of 269 married men. The team of Hutterite men included those who were infertile as well as those who had one or more child. Ober´s research looked mostly at genetic influence as opposed to non-genetic influences.
"Hutterites [forbid] contraception and uniformly desire large families, providing an outstanding population in which to study the genetics of normal human fertility," explained Ober in the statement.
The study discovered over 40 genetic regions that affected fertility in Hutterite males. Nine of the regions were also found to influence sperm-quality in non-Hutterite men. These regions stored genes that had many important biological functions, such as nucleotide binding, protein regulation, and immunity.
The project also helped the researchers better understand the various aspects of human fertility.
“We suggest that mutations in these genes that are more severe may account for some of the unexplained infertility (or subfertility) in the general population,” wrote the authors in the report.
Further studies may be needed to figure out if the mutations in these genes can somehow make sense to the unexplained cases of male fertility.