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| 2. |
- Binzer-Panchal, Amrei, et al.
(författare)
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Integrated Molecular Analysis of Undifferentiated Uterine Sarcomas Reveals Clinically Relevant Molecular Subtypes
- 2019
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Ingår i: Clinical Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 1078-0432 .- 1557-3265. ; 25:7, s. 2155-2165
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Undifferentiated uterine sarcomas (UUS) are rare, extremely deadly, sarcomas with no effective treatment. The goal of this study was to identify novel intrinsic molecular UUS subtypes using integrated clinical, histopathologic, and molecular evaluation of a large, fully annotated, patient cohort.Experimental Design: Fifty cases of UUS with full clinicopathologic annotation were analyzed for gene expression (n = 50), copy-number variation (CNV, n = 40), cell morphometry (n = 39), and protein expression (n = 22). Gene ontology and network enrichment analysis were used to relate over-and underexpressed genes to pathways and further to clinicopathologic and phenotypic findings.Results: Gene expression identified four distinct groups of tumors, which varied in their clinicopathologic parameters. Gene ontology analysis revealed differential activation of pathways related to genital tract development, extracellular matrix (ECM), muscle function, and proliferation. A multivariable, adjusted Cox proportional hazard model demonstrated that RNA group, mitotic index, and hormone receptor expression influence patient overall survival (OS). CNV arrays revealed characteristic chromosomal changes for each group. Morphometry demonstrated that the ECM group, the most aggressive, exhibited a decreased cell density and increased nuclear area. A cell density cutoff of 4,300 tumor cells per mm(2) could separate ECM tumors from the remaining cases with a sensitivity of 83% and a specificity of 94%. IHC staining of MMP-14, Collagens 1 and 6, and Fibronectin proteins revealed differential expression of these ECM-related proteins, identifying potential new biomarkers for this aggressive sarcoma subgroup. Conclusions: Molecular evaluation of UUS provides novel insights into the biology, prognosis, phenotype, and possible treatment of these tumors.
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- Hollfelder, Nina, et al.
(författare)
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Northeast African genomic variation shaped by the continuity of indigenous groups and Eurasian migrations
- 2017
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Ingår i: PLOS Genetics. - : PUBLIC LIBRARY SCIENCE. - 1553-7390 .- 1553-7404. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Northeast Africa has a long history of human habitation, with fossil-finds from the earliest anatomically modern humans, and housing ancient civilizations. The region is also the gateway out of Africa, as well as a portal for migration into Africa from Eurasia via the Middle East and the Arabian Peninsula. We investigate the population history of northeast Africa by genotyping similar to 3.9 million SNPs in 221 individuals from 18 populations sampled in Sudan and South Sudan and combine this data with published genome-wide data from surrounding areas. We find a strong genetic divide between the populations from the northeastern parts of the region (Nubians, central Arab populations, and the Beja) and populations towards the west and south (Nilotes, Darfur and Kordofan populations). This differentiation is mainly caused by a large Eurasian ancestry component of the northeast populations likely driven by migration of Middle Eastern groups followed by admixture that affected the local populations in a north-to-south succession of events. Genetic evidence points to an early admixture event in the Nubians, concurrent with historical contact between North Sudanese and Arab groups. We estimate the admixture in current-day Sudanese Arab populations to about 700 years ago, coinciding with the fall of Dongola in 1315/1316 AD, a wave of admixture that reached the Darfurian/Kordofanian populations some 400-200 years ago. In contrast to the northeastern populations, the current-day Nilotic populations from the south of the region display little or no admixture from Eurasian groups indicating long-term isolation and population continuity in these areas of northeast Africa.
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- Hollfelder, Nina, et al.
(författare)
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Patterns of African and Asian admixture in the Afrikaner population of South Africa
- 2020
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Afrikaner population of South Africa is the descendants of European colonists who started to colonize the Cape of Good Hope in the 1600s. In the early days of the colony, mixed unions between European males and non-European females gave rise to admixed children who later became incorporated into either the Afrikaner or the Coloured populations of South Africa. Differences in ancestry, social class, culture, sex ratio and geographic structure led to distinct and characteristic admixture patterns in the Afrikaner and Coloured populations. The Afrikaner population has a predominant European composition, whereas the Coloured population has more diverse ancestries. Genealogical records previously estimated the contribution of non-Europeans into the Afrikaners to be between 5.5 and 7.2%. RESULTS: To investigate the genetic ancestry of the Afrikaner population today (11-13 generations after initial colonization), we genotyped approximately five million genome-wide markers in 77 Afrikaner individuals and compared their genotypes to populations across the world to determine parental source populations and admixture proportions. We found that the majority of Afrikaner ancestry (average 95.3%) came from European populations (specifically northwestern European populations), but that almost all Afrikaners had admixture from non-Europeans. The non-European admixture originated mostly from people who were brought to South Africa as slaves and, to a lesser extent, from local Khoe-San groups. Furthermore, despite a potentially small founding population, there is no sign of a recent bottleneck in the Afrikaner compared to other European populations. Admixture amongst diverse groups from Europe and elsewhere during early colonial times might have counterbalanced the effects of a small founding population. CONCLUSIONS: While Afrikaners have an ancestry predominantly from northwestern Europe, non-European admixture signals are ubiquitous in the Afrikaner population. Interesting patterns and similarities could be observed between genealogical predictions and our genetic inferences. Afrikaners today have comparable inbreeding levels to current-day European populations.
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| 6. |
- Hollfelder, Nina, 1985-
(författare)
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Population genetic history and patterns of admixture : Examples from northeastern and southern Africa
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The origin of humans lies in Africa, as has been shown by archaeology, paleontology and genetics. Here, we can find the largest genetic diversity and the deepest split among human populations. African genetic diversity has been shaped by a long and complex history. In this thesis, I applied population genomic methods to investigate different aspects of the demographic history of Africa, specifically northeast and southern Africa.Both of these regions are population melting-pots, with many historically known major migrations.In northeast African populations, Eurasian admixture in central, northern, and eastern Sudanese populations was identified to be of Middle Eastern origin and the admixture time coincides with the Arab expansion. In northeast Africa I also studied alleles associated with lactase persistence, the ability to digest milk at an adult age. A wide diversity of these alleles was detected in Sudan, most commonly among pastoralists. The presence of a Middle Eastern LP-allele and absence of a European LP-allele is consistent with the admixture pattern observed in the first paper.I deciphered the patterns of genetic admixture in the Afrikaner population of South Africa and compared admixture patterns of the X-chromosome and autosomes to disentangle sex-biased admixture in southern African populations.The Afrikaner were shown to carry on average 5% non-European admixture, mostly from Khoe-San, East and South Asian sources. The admixture was sex-biased, with larger contributions from European males and admixture with Africans can be dated to 9-10 generations ago – fitting previous genealogical estimates of the age and the history of the population.Bantu-speaker/Khoe-San contact shows a pattern of female Bantu-speaker bias, which is conflicting with previous mtDNA and Y-chromosome studies. A change in mate-choice over time could explain this discrepancy.This thesis contributes to a deeper understanding of African demographic history in general and of some previously understudied populations and geographic areas in particular.
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| 7. |
- Hollfelder, Nina, et al.
(författare)
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The deep population history in Africa
- 2021
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Ingår i: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 30:R1, s. R2-R10
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Forskningsöversikt (refereegranskat)abstract
- Africa is the continent with the greatest genetic diversity among humans and the level of diversity is further enhanced by incorporating non-majority groups, which are often understudied. Many of today's minority populations historically practiced foraging lifestyles, which were the only subsistence strategies prior to the rise of agriculture and pastoralism, but only a few groups practicing these strategies remain today. Genomic investigations of Holocene human remains excavated across the African continent show that the genetic landscape was vastly different compared to today's genetic landscape and that many groups that today are population isolate inhabited larger regions in the past. It is becoming clear that there are periods of isolation among groups and geographic areas, but also genetic contact over large distances throughout human history in Africa. Genomic information from minority populations and from prehistoric remains provide an invaluable source of information on the human past, in particular deep human population history, as Holocene large-scale population movements obscure past patterns of population structure. Here we revisit questions on the nature and time of the radiation of early humans in Africa, the extent of gene-flow among human populations as well as introgression from archaic and extinct lineages on the continent.
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| 8. |
- Hollfelder, Nina, et al.
(författare)
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The Genetic Variation of Lactase Persistence Alleles in Sudan and South Sudan
- 2021
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Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653 .- 1759-6653. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Lactase persistence (LP) is a well-studied example of a Mendelian trait under selection in some human groups due to gene-culture coevolution. We investigated the frequencies of genetic variants linked to LP in Sudanese and South Sudanese populations. These populations have diverse subsistence patterns, and some are dependent on milk to various extents, not only from cows but also from other livestock such as camels and goats. We sequenced a 316-bp region involved in regulating the expression of the LCT gene on chromosome 2, which encompasses five polymorphisms that have been associated with LP. Pastoralist populations showed a higher frequency of LP-associated alleles compared with nonpastoralist groups, hinting at positive selection also among northeast African pastoralists. Among the LP variants, the -14009:G variant occurs at the highest frequency among the investigated populations, followed by the -13915:G variant, which is likely of Middle Eastern origin, consistent with Middle Eastern gene flow to the Sudanese populations. There was no incidence of the “East African” LP allele (-14010:C) in the Sudanese and South Sudanese groups, and only one heterozygous individual for the “European” LP allele (-13910:T), suggesting limited recent admixture from these geographic regions. The Beja population of the Beni Amer show three different LP variants at substantial and similar levels, resulting in one of the greatest aggregation of LP variants among all populations across the world.
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| 10. |
- Sanchez-Quinto, Federico, et al.
(författare)
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Megalithic tombs in western and northern Neolithic Europe were linked to a kindred society
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 116:19, s. 9469-9474
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Tidskriftsartikel (refereegranskat)abstract
- Paleogenomic and archaeological studies show that Neolithic lifeways spread from the Fertile Crescent into Europe around 9000 BCE, reaching northwestern Europe by 4000 BCE. Starting around 4500 BCE, a new phenomenon of constructing megalithic monuments, particularly for funerary practices, emerged along the Atlantic facade. While it has been suggested that the emergence of megaliths was associated with the territories of farming communities, the origin and social structure of the groups that erected them has remained largely unknown. We generated genome sequence data from human remains, corresponding to 24 individuals from five megalithic burial sites, encompassing the widespread tradition of megalithic construction in northern and western Europe, and analyzed our results in relation to the existing European paleogenomic data. The various individuals buried in megaliths show genetic affinities with local farming groups within their different chronological contexts. Individuals buried in megaliths display (past) admixture with local hunter-gatherers, similar to that seen in other Neolithic individuals in Europe. In relation to the tomb populations, we find significantly more males than females buried in the megaliths of the British Isles. The genetic data show close kin relationships among the individuals buried within the megaliths, and for the Irish megaliths, we found a kin relation between individuals buried in different megaliths. We also see paternal continuity through time, including the same Y-chromosome haplotypes reoccurring. These observations suggest that the investigated funerary monuments were associated with patrilineal kindred groups. Our genomic investigation provides insight into the people associated with this long-standing megalith funerary tradition, including their social dynamics.
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