Mitochondial DNA diversity in Mennonite communities from the Midwestern United States

Human Biology Volume 82,issue 3

Phillip E. Melton, MJ Mosher, R. Rubicz, M. Zlojutro, MH Crawford

This study examined mitochondrial DNA (mtDNA) variation in six Mennonite communities from Kansas (Goessel, Lone Tree, Garden View, Meridian, and Garden City) and Nebraska (Henderson) in order to determine their genetic structure and its relationship to population history. Mitochondrial DNA haplogroup and haplotype information were obtained for 118 individuals from blood samples. Molecular genetic variation was analyzed using diversity measures, neutrality test statistics, spatial analysis of molecular variance (SAMOVA), and multidimensional scaling plots. The Mennonite samples exhibited eight western European mtDNA haplogroups – H, HV0, I, J, K, T, U, and X. Comparable to other populations of European descent, haplogroup H was the most frequent in all six communities and ranged from 35% in Lone Tree to 75% in Old Order Mennonites from Garden City, Kansas. A total of 58 different mtDNA haplotypes were found in these groups with only one shared among all six populations. Haplotype diversities varied from 0.81 in Goessel to 0.96 in Henderson and Garden View. Multivariate statistical analysis of these populations indicates that these Anabaptist communities formed new congregations by fissioning along familial lines. Population subdivision of these communities into congregations support previously documented patterns of fission-fusion. In conclusion these haploid molecular data provide a more accurate reflection of biological relationships between Midwestern Mennonite communities than evidence based on classical genetic markers.

mood disorders and schizophrenia in genetically isolated populations

Chasing genes for mood disorders and schizophrenia in genetically isolated populations

Tine Venken 1 2, Jurgen Del-Favero 1 2 Abstract

Major affective disorders and schizophrenia are among the most common brain diseases worldwide and their predisposition is influenced by a complex interaction of genetic and environmental factors. So far, traditional linkage mapping studies for these complex disorders have not achieved the same success as the positional cloning of genes for Mendelian diseases. The struggle to identify susceptibility genes for complex disorders has stimulated the development of alternative approaches, including studies in genetically isolated populations. Since isolated populations are likely to have both a reduced number of genetic vulnerability factors and environmental background and are therefore considered to be more homogeneous compared to outbred populations, the use of isolated populations in genetic studies is expected to improve the chance of finding susceptibility loci and genes. Here we review the role of isolated populations, based on linkage and association studies, in the identification of susceptibility genes for bipolar disorder and schizophrenia.

Hum Mutat 0, 1-15, 2007. © 2007 Wiley-Liss, Inc.>