Из работы Тыну Эско (Tõnu Esko 2009)

Генетические барьеры из работы Манфреда Кайзера

It makes sense that latitudinal genetic variation would be greater than longitudinal variation. People accustomed to a certain climate - especially farmers - would be more likely to spread quickly along east-west lines, since places that have similar latitudes tend to have similar climates; people who are adapted to live at a given location are more likely to be comfortable 500 miles due east or west of that location than 500 miles due north or south. So it would take longer for populations to spread north or south, which would allow more time for genetic changes to emerge.

There are the Alps, too, of course. They run generally east-west, and serve to partially block the Italian peninsula from the rest of Europe. This relative isolation is probably why the Italian populations are among the most genetically peripheral in Europe.

And then there are the Finns. They don't even genetically overlap with other groups in the study, according the metric the authors are using - in fact, they're not even close; they're way off by themselves in the upper right-hand corner. According to the NYT, the genetic barrier between the Finns and the rest of Europe "arose because the Finnish population was at one time very small and then expanded, bearing the atypical genetics of its few founders."

    Interestingly, PC analysis was also capable of highlighting intra-population differences, such as between the two Finnish and the two Italian samples, respectively. A low level of intra-population differentiation in Germany has been reported previously [18], and was confirmed here. In addition, we detected intra-population differences within the Czech and Estonian samples (Figure S3).

The two Finnish samples were from Helsinki and Kuusamo. The German>Using principal component (PC) analysis, we studied the genetic constitution of 3,112 individuals from Europe as portrayed by more than 270,000 single nucleotide polymorphisms (SNPs) genotyped with the Illumina Infinium platform. In cohorts where the sample size was >100,>The first two PCs highlight the genetic diversity corresponding to the northwest to southeast gradient and position the populations according to their approximate geographic origin. The resulting genetic map forms a triangular structure with a) Finland, b) the Baltic region, Poland and Western Russia, and c) Italy as its vertexes, and with d) Central- and Western Europe in its centre. Inter- and intra- population genetic differences were quantified by the inflation factor lambda (λ) (ranging from 1.00 to 4.21), fixation index (Fst) (ranging from 0.000 to 0.023), and by the number of markers exhibiting significant allele frequency differences in pair-wise population comparisons. The estimated lambda was used to assess the real diminishing impact to association statistics when two distinct populations are merged directly in an analysis. When the PC analysis was confined to the 1,019 Estonian individuals (0.1% of the Estonian population), a fine structure emerged that correlated with the geography of individual counties. With at least two cohorts available from several countries, genetic substructures were investigated in Czech, Finnish, German, Estonian and Italian populations. Together with previously published data, our results allow the creation of a comprehensive European genetic map that will greatly facilitate inter-population genetic studies including genome wide association studies (GWAS).

Zones of sharp genetic change in Europe are also linguistic boundaries

GUIDO BARBUJANI AND ROBERT R. SOKAL

*Dipartimento di Biologia, Universita di Padova, via Trieste 75, I-35121 Padova, Italy; and tDepartment of Ecology and Evolution, State University of New
York, Stony Brook, NY 11794-524

Также интересно сравнить генетические барьеры (по анализу доступного исследователяи генома)
с гаплогруппными барьерами

http://forum.molgen.org/index.php/topic,738.0.html