“In the study, 12 specific areas of the DNA sequence were identified that are significantly associated both with the age at which we have our first child and the total number of children we have during the course of our life,” said Dr. Christian Gieger, summarizing the findings. He heads the Research Unit ‘Molecular Epidemiology’ at Helmholtz Zentrum München (HMGU) and was also involved in the research.
The study contains an analysis of 62 data sets, also from the Augsburg KORA study, with information from 238,064 men and women for age at first birth and from almost 330,000 men and women for the number of children.
“Until now, human reproductive behavior was thought to be mainly linked to personal choices or social circumstances and environmental factors,” said Professor Konstantin Strauch, director of the Institute of Genetic Epidemiology at HMGU, who was also involved in the study. “The new findings show that there is also a genetic basis for reproductive behavior.”
In addition, the authors reported that DNA variants linked with age at the birth of the first child are associated with other characteristics of reproductive and sexual development, such as the age at which girls have their first period, age at voice break in boys or age of menopause onset in women.
The authors see in the current study a possible game changer for research into human development and fertility. However, it is important to keep these results in perspective: The researchers calculated that the identified DNA variants together predict less than one percent of the timing at which men and women have their first child or of the number of children they have in the course of their lifetime.
“By examining the function of the 12 DNA regions, 24 genes were identified that are likely responsible for the effects on reproductive behavior,” said co-author PD Dr. Doris Stöckl. She is a researcher at the Institute of Epidemiology II of HMGU in the research group of Professor Christa Meisinger, who added: “Some of these genes were already known to influence infertility risk, while others have not yet been studied in this context.” The researchers hope that an improved understanding of the function of these genes may provide new insights for infertility treatments.
Barban, N. et al. (2016): Genome-wide analysis identifies 12 loci influencing human reproductive behavior. Nature Genetics, doi: 10.1038/ng.3698
The Helmholtz Zentrum München, the German Research Center for Environmental Health, pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München is headquartered in Neuherberg in the north of Munich and has about 2,300 staff members. It is a member of the Helmholtz Association, a community of 18 scientific-technical and medical-biological research centers with a total of about 37,000 staff members.
The Research Unit of Molecular Epidemiology (AME) analyses population-based cohorts and case studies for specific diseases, using genomics, epigenomics, transcriptomics, proteomics, metabolomics and functional analyses. The aim of this research unit is to decipher the molecular mechanisms of complex diseases like type 2 diabetes or obesity. The unit administers the biological specimen repository of the Department of Epidemiology and stores the samples for national and international projects.
The Institute of Epidemiology II (EPI II) focuses on the assessment of environmental and lifestyle risk factors which jointly affect major chronic diseases such as diabetes, heart disease and mental health. Research builds on the unique resources of the KORA cohort, the KORA myocardial infarction registry, and the KORA aerosol measurement station. Aging-related phenotypes have been added to the KORA research portfolio within the frame of the Research Consortium KORA-Age. The institute’s contributions are specifically relevant for the population as modifiable personal risk factors are being researched that could be influenced by the individual or by improving legislation for the protection of public health.
Research at the Institute of Genetic Epidemiology (IGE) focuses on planning, realization and analysis of projects regarding the identification of genetic factors responsible for complex traits. This involves application, further development and implementation of a variety of statistical methods to address specific aspects such as rare genetic variants, mitochondrial DNA, gene-gene and gene-environment interactions, family studies, and the handling of population structures. The elucidation of disease-relevant genetic factors as well as their inclusion into models of disease risk provides the basis of individualized approaches to treatment or prevention.
For almost 30 years, the Cooperative Health Research in the Region of Augsburg (KORA) has been examining the health of thousands of citizens in Augsburg and environs. The aim of the project is to increase understanding of the impact of environmental factors, behaviour and genes on human health. The KORA studies focus on matters relating to the development and progression of chronic diseases, in particular myocardial infarction and diabetes mellitus. To that end, research is conducted into risk factors arising from lifestyle factors (including smoking, diet and exercise), environmental factors (including air pollution and noise) and genetics. Questions relating to the use and cost of health services are examined from the point of view of health services research.