Research Areas
Genomic Imprinting in the Placenta
The placenta is the most understudied organ and yet plays a critical role in the transfer of nutrition from mother to fetus. We are using RNA-seq and DNA-methylation to find out if genomic imprinting in the placenta plays a role in the transmission of stunting and other parental phenotypes to the next generation.
Developmental Origins of High Blood Pressure
We used mediation analysis to show that being one SD heavier in childhood (age 1 to 10 years) was associated with an average gain in adult stature of 3 cm for females and 4 cm for males by age 21 years. Meanwhile increased risk for obesity and hypertension was negligible.
Placental Malaria and Child Growth
Sulfadoxine-pyrimethamine (SP) is an intermittent preventive treatment (IPTp) for malaria during pregnancy. Women who received no doses of SP during pregnancy experienced the most disadvantageous birth outcomes. They tended to be younger and to have had no primary school education.
Religion
Using behavioral, hormonal, and genetic data, we investigated the role of religion, especially menstrual taboos, in preventing cuckoldry. Presently, we are exploring the causes of religious conversion in the Dogon.
Polygyny
I provided the first prospective, longitudinal data set on polygyny and child mortality. Dogon children fared much better under monogamy and women in polygynous marriages had lower reproductive success.
Menstruation
My research on the Dogon provided the first longitudinal data on menstruation in a population that did not practice contraception. It showed that a regular monthly period is not “normal,” and was significant for the design of hormonal contraceptives and shed light on breast cancer risk. It falsified the myth of menstrual synchrony and deepened the understanding of the evolution of menstruation.
Cooperative Breeding
My research on “cooperative breeding” has encouraged more critical assessments of the dynamics of kin cooperation and competition.
Life History Theory
Life history theory posits that organisms face a trade-off between female fertility and offspring survivorship. Efforts to demonstrate this trade-off in human forager populations were unsuccessful. Using data from the Dogon, I provided the first clear evidence for the predicted nonlinear relationship between fertility and reproductive success in a human population.
Height and Educational Attainment
My team is investigating differences in educational attainment between boys and girls, with a particular focus on the roles of height and gender norms.
Ethical Note
The placenta is the most understudied organ. The neglect of the placenta in research needs to be rectified since the placenta plays a vital role in the health of a woman and her fetus during pregnancy. Moreover, the placenta has a lifelong influence on the health of both mother and child. Our research group is studying the placenta in order to shed light on health vulnerabilities in adulthood that trace their origins to the expression of genes in the placenta. We focus on the “imprinted genes” as this is a class of genes that matter for growth. We seek to understand the role of imprinted genes in determining how well the fetus grows and how the baby will be impacted by the mother’s environmental exposures, especially her nutrition during childhood. By doing this research in Mali, we hope to shed light on health problems that are especially prevalent in low-income countries where under-nutrition is a major problem. Since people in high-income countries tend to suffer from over- instead of under- nutrition, there has been insufficient investment in this kind of research. We are doing basic science that is intended to furnish insights on epigenetic processes that will promote human health in the future.
All of our research protocols were approved by the ethical review boards of the University of Michigan (HUM00043670), and the University of Bamako Medical Faculty (No. 2016/68/CD/FMPOS), and the Malian Government (N o 02/ 2024-MESRS/CNRST). We explained the research to local stake-holders and obtained permission. Most importantly, informed consent was obtained from all mothers and their families well in advance of delivery and before including them in any research protocols. The placental dissections were carried out by Malian midwives under the supervision of a Malian physician. The protocol entailed taking about a gram of placental tissue as well as about a gram of umbilical cord tissue and 3 mL of cord blood. The placentas and umbilical cord were returned to the families immediately afterward. In the Dogon, there is no special rite associated with the placenta. The midwives who collaborated on this research were never tasked at the same time with the care of the mother and newborn. No problems or adverse incidents were encountered and the placental collections concluded in April 2020 just prior to the COVID-19 pandemic.