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- Lao, O., et al.
(författare)
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Correlation between Genetic and Geographic Structure in Europe
- 2008
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 18:16, s. 1241-1248
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the genetic structure of the European population is important, not only from a historical perspective, but also for the appropriate design and interpretation of genetic epidemiological studies. Previous population genetic analyses with autosomal markers in Europe either had a wide geographic but narrow genomic coverage [1, 2], or vice versa [3-6]. We therefore investigated Affymetrix GeneChip 500K genotype data from 2,514 individuals belonging to 23 different subpopulations, widely spread over Europe. Although we found only a low level of genetic differentiation between subpopulations, the existing differences were characterized by a strong continent-wide correlation between geographic and genetic distance. Furthermore, mean heterozygosity was larger, and mean linkage disequilibrium smaller, in southern as compared to northern Europe. Both parameters clearly showed a clinal distribution that provided evidence for a spatial continuity of genetic diversity in Europe. Our comprehensive genetic data are thus compatible with expectations based upon European population history, including the hypotheses of a south-north expansion and/or a larger effective population size in southern than in northern Europe. By including the widely used CEPH from Utah (CEU) samples into our analysis, we could show that these individuals represent northern and western Europeans reasonably well, thereby confirming their assumed regional ancestry. © 2008 Elsevier Ltd. All rights reserved.
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| 2. |
- Kostareli, E., et al.
(författare)
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Intraclonal diversification of immunoglobulin light chains in a subset of chronic lymphocytic leukemia alludes to antigen-driven clonal evolution
- 2010
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 24:7, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- The study of intraclonal diversification (ID) in immunoglobulin (IG) genes offers valuable insight into the role of ongoing interactions with antigen in lymphomagenesis. We recently showed that ID in the IG heavy chain genes of patients with chronic lymphocytic leukemia (CLL) was generally limited; however, intense ID was evident in selected cases, especially those expressing stereotyped IGHV4-34 rearrangements and assigned to subset 4. Here, we report results from a large-scale subcloning study of IG light variable genes, in a total of 1008 subcloned sequences from 56 CLL cases. Multiple analogies were noted between heavy and light chains regarding the occurrence and molecular features of ID. More specifically, the impact of ID on the clonotypic light chains was generally low, with the significant exception of subset 4. Similar to the IGHV4-34 heavy chains of this subset, their partner IGKV2-30 light chains were affected by an active and precisely targeted ID process. Altogether, these findings strengthen the argument that stereotypy in subset 4 extends to stereotyped ID patterns for both heavy and light chains through persistent antigenic stimulation. Furthermore, they strongly suggest that light chains have an active role in the antigen selection process, at least for certain subsets of CLL cases.
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