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KU laboratory instrumental in understanding Mennonite genetics

Monday, May 01, 2017

LAWRENCE — For most of its 40-year history, the Laboratory of Biological Anthropology at the University of Kansas has worked with Mennonite communities in the Midwest to better understand their evolutionary history dating back to the Protestant Reformation.

A recent study published in Human Biology in a special issue that honors the anniversary of the lab's founding demonstrates clear evidence that Mennonite groups in Kansas and Nebraska share genetic affinities with central and northern Europe, areas where the group originated.

Michael Crawford, professor of anthropology and founder of the lab, said the study provides a more balanced examination of Mennonite genetic ancestry because the group has undergone a significant "bottleneck" over the last 300 years.

"The population reduced significantly in size," said Crawford, a co-author of the study. "It's obvious who is left after many of them emigrated out of Russia to the United States."

The results that examined the Y chromosome, or NRY haplogroup, yielded genetic profiles that provided additional information to researchers that could possibly allow them to link together different groups based on their paternal genetic lines.  

"It helps us reconstruct settlement patterns and understand how genes interact with the environment," Crawford said.

Co-authors for the study included Kristine Beaty, a KU doctoral candidate in the lab; M.J. Mosher, of the Western Washington University Department of Anthropology, and Phillip Melton, of the Centre for Genetic Origins of Health and Disease at the University of Western Australia. Mosher and Melton are KU alumni who also studied under Crawford as part of the Lab of Biological Anthropology.

The special Human Biology issue dedicated to the lab's history features publications from several of Crawford's former students, as he has mentored 36 doctoral students and 20 postdoctoral researchers since opening the lab, which has served as a staple in building the tradition of the anthropological genetics program at KU.

Another former Crawford student, renowned researcher Dennis O'Rourke, Foundation Professor of Anthropology, returned to KU in 2016 and will take over as director of the lab as Crawford enters phased retirement.

Crawford said the journal issue is a nice tribute to the lab and to anthropological genetics, a field that has advanced understanding the patterns and causes of genetic variation within and among populations. Researchers have worked on a wide range of discoveries from the peopling of the Americas to how genetic makeup factors into the spread of diseases and other health issues.

"There is a big health component to understanding genetic interaction with environmental factors in complex diseases, such as diabetes, cancer, lymphoma, hypertension and obesity," he said. "And these are areas that the genetic epidemiologists have been on the forefront of addressing."

Part of the appeal of studying the genetics of Mennonites is that for the most part, based on their lifestyle, they don't participate in habits that are destructive to their health, such as smoking or drinking alcohol.

"Most of them age at a different rate than the general population," Crawford said. "That allows us to look at to what extent is this biological aging on the genetic control? And to what extent is the aging environmental?"

Using DNA to reconstruct past history can also provide benefits to health researchers in the future, he said.

"This journal issue highlights the tremendous accomplishments of the students and this lab over 40 years of research," Crawford said.

Other articles in the journal issue were all written by former students and postdoctoral researchers who were members of the Lab of Biological Anthropology:

  • "Finding Rare, Disease-Associated Variants in Isolated Groups: Potential Advantages of Mennonite Populations," by Fabiana Lopes, Liping Hou, Angelica B.W. Boldt, Layla Kassem, Veronica Alves, Antonio Nardi and Francis McMahon.
  • "Patterns of DNA Methylation across the Leptin Core Promoter in Four Diverse Asian and North American Populations," by M.J. Mosher, P. E. Melton, P. Stapleton, M.S. Schanfield and Crawford
  • "Genetic Affiliation of Pre-Hispanic and Contemporary Mayas through Maternal Linage," by Mirna Isabel Ochoa-Lugo, María de Lourdes Muñoz, Gerardo Pérez-Ramírez, Beaty, Mauro López-Armenta, Javiera Cervini-Silva, Miguel Moreno-Galeana, Adrián Martínez Meza, Eduardo Ramos, Crawford and Arturo Romano-Pacheco.
  • "Population History and Mitochondrial Genetic Substructure of the Rama Amerindians from Nicaragua" by Norberto Baldi and Crawford.

The journal was founded in 1929 by eminent biologist Raymond Pearl, and the current special issue is the only one in the journal's history devoted entirely to the founding of the Laboratory of Biological Anthropology. The issue also incorporated to include studies by O'Rourke, who will take over the lab's director, and assistant director Jennifer Raff, KU assistant professor of anthropology.

Image: This map shows Mennonite communities that participated in this study along with their paternal genetic structures. Source: Journal of Human Biology