Now: Genetic Traces of Religions in Lebanese and Iranians
Then: Rare Genetic Disorders in Finnish Mitochondrial Haplotypes (U)
Now: Genome-Wide Association Studies in Saami
The whole business of direct-to-the-consumer DNA tests was founded upon the revelation in 1997 that Jewish men with the last name Cohen ("priest" in Hebrew) or something similar often preserved the genetic signature of Old Testament priests in the Y chromosome type handed down from father to son. Last year at long last, the so-called Cohen Modal Haplotype was completely pinned down and defined to everyone's satisfaction ("Does He or Doesn't He?"). Now similar genetic traces are being sought, and found, for other religions from the Middle East.
In response to customers asking whether being a Jew was a matter of ancestry or culture, genes or religion, I used to say, "Genes don't have religion, genes are older than religions, your DNA doesn't know what religion you are." But the increasingly adept methods of populations genetics are changing that pat response. The key tool is a program that uses advanced statistics to estimate population differentiations, BATWING. Standing for Bayesian Analysis of Trees With Internal Node Generation, this software can calculate the effective population sizes and growth rates from microsatellite data, assuming there was a split into several populations in the past. It is a little over 10 years old. The following article is likely to become a classic in this regard:
European Journal of Human Genetics (2011) 19, 334–340; doi:10.1038/ejhg.2010.177; published online 1 December 2010
Cultural expansions, including of religions, frequently leave genetic traces of differentiation and in-migration. These expansions may be driven by complex doctrinal differentiation, together with major population migrations and gene flow. The aim of this study was to explore the genetic signature of the establishment of religious communities in a region where some of the most influential religions originated, using the Y chromosome as an informative male-lineage marker. A total of 3139 samples were analyzed, including 647 Lebanese and Iranian samples newly genotyped for 28 binary markers and 19 short tandem repeats on the non-recombinant segment of the Y chromosome. Genetic organization was identified by geography and religion across Lebanon in the context of surrounding populations important in the expansions of the major sects of Lebanon, including Italy, Turkey, the Balkans, Syria, and Iran by employing principal component analysis, multidimensional scaling, and AMOVA. Timing of population differentiations was estimated using BATWING, in comparison with dates of historical religious events to determine if these differentiations could be caused by religious conversion, or rather, whether religious conversion was facilitated within already differentiated populations. Our analysis shows that the great religions in Lebanon were adopted within already distinguishable communities. Once religious affiliations were established, subsequent genetic signatures of the older differentiations were reinforced. Post-establishment differentiations are most plausibly explained by migrations of peoples seeking refuge to avoid the turmoil of major historical events.
Meanwhile, in Autosomal DNA
A like expansion and intensification of research interests has also transformed the field of Finnish DNA. In the old days it was well appreciated, through the work of Finnila and others, that the people of Finland, Estonia, Sweden and neighboring regions in Russia had a peculiar genetic history. Strangely, at least on the basis of mitochondrial DNA, they were more closely related to the Berbers of North Africa than the neighboring Swedes, Poles, Lithuanians and Russians. Female haplogroups UK were associated with a risk of occipital stroke, migraine and other neuro-deficiencies. On another level, their unique genetic history was approached through the study of male haplogroup N, common among Laplanders and Saami.
The focus has now shifted from haplotyping and sex-linked genes to population genetics and autosomal DNA just as it has in consumer tests. After 10 years, an important autosomal study of the Saami has revolutionized the subject and shows promise of becoming the pilot to a new series of genome-wide disease association studies.
European Journal of Human Genetics (2011) 19, 347–352; doi:10.1038/ejhg.2010.179; published online 8 December 2010
The understanding of patterns of genetic variation within and among human populations is a prerequisite for successful genetic association mapping studies of complex diseases and traits. Some populations are more favorable for association mapping studies than others. The Saami from northern Scandinavia and the Kola Peninsula represent a population isolate that, among European populations, has been less extensively sampled, despite some early interest for association mapping studies. In this paper, we report the results of a first genome-wide SNP-based study of genetic population structure in the Finnish Saami. Using data from the HapMap and the human genome diversity project (HGDP-CEPH) and recently developed statistical methods, we studied individual genetic ancestry. We quantified genetic differentiation between the Saami population and the HGDP-CEPH populations by calculating pair-wise FST statistics and by characterizing identity-by-state sharing for pair-wise population comparisons. This study affirms an east Asian contribution to the predominantly European-derived Saami gene pool. Using model-based individual ancestry analysis, the median estimated percentage of the genome with east Asian ancestry was 6% (first and third quartiles: 5 and 8%, respectively). We found that genetic similarity between population pairs roughly correlated with geographic distance. Among the European HGDP-CEPH populations, FST was smallest for the comparison with the Russians (FST=0.0098), and estimates for the other population comparisons ranged from 0.0129 to 0.0263. Our analysis also revealed fine-scale substructure within the Finnish Saami and warns against the confounding effects of both hidden population structure and undocumented relatedness in genetic association studies of isolated populations.
The key to emerging triumphs of research here is the international HapMap project.
On two fronts--religious history and rare diseases--genetics has brought more advances in the past decade than in the previous century before that. That consumers can take part in these exciting developments by ordering an affordable autosomal analysis of their entire ancestry or confirming the paternity of their child with a simple test purchased at their local drugstore is a tribute to the present golden age of American science and industry.