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- Salojarvi, Jarkko, et al.
(författare)
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Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch
- 2017
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Ingår i: Nature Genetics. - : NATURE PUBLISHING GROUP. - 1061-4036 .- 1546-1718. ; 49:6, s. 904-912
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Tidskriftsartikel (refereegranskat)abstract
- Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.
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| 2. |
- Norberg-Spaak, Lena, et al.
(författare)
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Adenoid cystic carcinoma : Use of cell proliferation, bcl-2 expression, histologic grade, and clinical stage as predictors of clinical outcome
- 2000
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Ingår i: Head and Neck. - 1043-3074 .- 1097-0347. ; 22:5, s. 489-497
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Tidskriftsartikel (refereegranskat)abstract
- Background. Although the three basic histologic growth patterns of adenoid cystic carcinomas (tubular, cribriform, and solid) provide some indication of clinical outcome, additional, perhaps superior, predictors of biologic activity are needed for patient management. Methods. This series is composed of 31 adenoid cystic carcinomas that presented in Linkoping between 1982 and 1997. The tumors were clinically staged and histologically graded. For each case, after immunohistochemical identification, the proportion of tumor cells expressing the cell cycle markers MIB-1 and bcl-2 (as an indicator of proliferation and apoptosis, respectively) were quantified. Statistical correlation was sought between tumor stage and grade and the two cell cycle markers. Results. The proportions of cycling tumor cells in adenoid cystic carcinomas ranged from 0.3% to 55%. For patients with no evidence of disease and a follow-up of at least 5 years, the mean percent MIB-1 value was significantly lower than for those patients who were alive with local recurrence and/or metastasis or who had died from their adenoid cystic carcinoma (p = .024). MIB-1 tumor cell positivity also correlated strongly with tumor grade (p = .053), but not with stage (p = .22). Neither clinical stage nor histologic grade correlated with the degree of bcl-2 tumor cell positivity (p = .97 and p = .49, respectively). Conclusions. Staging and grading continue to play a vital role in the management of patients with adenoid cystic carcinoma. Furthermore, in this series of patients with adenoid cystic carcinoma, a cycling tumor cell population as measured by the MIB-1 antibody greater than 10% indicates this group as biologically more aggressive and at an increased risk for a fatal course. (C) 2000 John Wiley and Sons, Inc.
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