PMC:2427286 / 19176-22696
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2_test
{"project":"2_test","denotations":[{"id":"18374297-10331250-2052372","span":{"begin":263,"end":265},"obj":"10331250"},{"id":"18374297-15795887-2052373","span":{"begin":2800,"end":2802},"obj":"15795887"}],"text":"Evidence for Migration from Haplotype Structure\nFinally, we investigated the possible origins of the J∗(xJ2), I, and R1b chromosomes in more detail by using information from the STR haplotypes. We visualized STR haplotypes within each haplogroup by using networks28 constructed with the nine Y-STRs common to all datasets. Geographical structure was seen in the I and R1b networks (Figure 3), but not in the J∗(xJ2) network. The geographical distributions of Lebanese haplotypes were then investigated in the Y chromosome Haplotype Reference Database43 (YHRD, release 21) with seven Y-STRs so that 51,253 entries from 447 populations could be interrogated. Of the 30 Lebanese R1b haplotypes, six (representing seven individuals) were absent from the database, and 22 of the remaining 24 showed distributions that included Europe and western Asia, as would generally be expected. Most of these haplotypes thus did not provide more precise subregional information about their likely place of origin.\nOne haplotype (WES1, Western European Specific 1), however, stood out for two reasons. First, it showed a common but strictly western European distribution among the indigenous populations in the YHRD; it was present in 26/81 European populations west of Hungary and in zero populations east of this longitude (Figure 4). Second, and in contrast to its distribution in the database, it was the most common R1b haplotype in the Lebanese Christians tested (5/27, 19% of R1b, or about 2% of the total Lebanese Christian haplotypes).\nBecause this Lebanese occurrence lies far outside the normal range of this haplotype, we investigated how likely a haplotype was to rise to this frequency by chance. The first test considered the chances of observing modern levels of the WES1 haplotype among Lebanese Christians without any migration. No WES1 members were found in \u003e1,000 Middle Eastern individuals in the YHRD. Making the highly conservative assumption that its frequency p0 in the Middle East outside the Lebanese Christians was ∼0.1% (the maximum observed size consistent with zero in the sample) and a male effective population size of NL ≈1000 for the Lebanese Christians estimated from our data with BATWING, we calculated the probability of observing the modern fraction f of 2% or more as \u003c0.02 (Material and Methods). In contrast, given an input of western Europeans, selected from an evolving effective population NE ≈5000, who were carrying WES1 at 0.21% (the weighted average of the YHRD frequencies from England, France, Germany, and Italy), the probability of reaching 2% or more among Lebanese Christians exceeded 0.05 for an admixing population fraction m of ∼10.6% or greater (Table 7). It has been assumed that a total of 32 generations have passed since the start of the admixture event44, with mixing only during the first seven generations. Thus, WES1 is likely to have originated in western Europe and shows exactly the pattern expected for a European lineage introduced by the Crusaders.\nLikewise, one can test the question of whether the difference in J∗(xJ2) frequencies between Muslims (25%) and non-Muslims (15%) would have emerged by drift without enhancement during the Islamic expansion from the Arabian Peninsula by considering the probability that the 15% frequency could have drifted up to 25% or more by chance in the ∼42 generations since the Islamic expansion. For an assumed effective population size of ∼5,000, this is 0.0023, and thus, again, admixture seems likely to have contributed."}